Why do high level chess players consistently make really strange looking moves?

There is a diff. Beginners don't know what the rules are so they break them on every move.

Top players not only know the rules but they also know the exceptions to those rules, and hence they break rules every now and then, knowing the exceptions are fine.

Mid range players know the rules, but don't know the exceptions, and hence they follow they rules.

Not all principles are equal - some are more advanced than others. The more advanced principles tend to be more detailed and specific to certain situations, and could override the basic ones. Kallatroh gave such an advanced idea: "Closed positions are of course full of maneuvering." Once you are aware of this idea, you should see that these "strange" moves are in fact following more advanced principles, which on a superficial level seem to contradict basic opening principles of development.

A quick analogy is the basic principle of "don't leave your pieces en prise". Imagine a complete novice who knows this rule coming across a collection of positions showing brilliant sacrifices. This beginner might say, "Why do these top players keep making these strange moves where they leave their pieces unprotected, like beginners?" Obviously sacrifices are a more advanced idea that overrides the en prise principle. 

I don't understand why my c1 bishop is better than black's g7 bishop? If anything, I feel like black's g7 bishop is more important than my c1 bishop because he needs it to defend the dark squares around his king, whereas the white king is safer and doesn't need his DS bishop.

Admittedly I'm not an expert on pawn structure. I'm a tactical player and I usually just always go after my opponent's king, trying to keep the game as open as possible. Is that a bad strategy?

Tactics are easier to understand than strategy though. I can understand when a see a grandmaster play a strong tactical move because I can go through the calculation and see how it would play out a different way. But a positional sacrifice, for example, is a lot harder to comprehend than a tactical sacrifice.

Hold my beer.

http://www.chessgames.com/perl/chessgame?gid=1380585

Just read the comments...

The sacred "principles" the OP is citing are, in fact, the principles of the open game. Blindly applying them to every opening and pawn formation is a recipe for disaster. It's the kind of thinking that makes less-experienced players put their knights on c3 and c6 in queen-pawn openings and to develop all their pieces in front of their pawns in closed positions, leaving them to suffocate from the lack of pawn breaks. 

When two players do the same thing, it isn't the same! The beginner plays ...Nh5 for a one-move attack on an enemy bishop; the master plays ...Nh5 to maneuver his knight to f4, or to clear the way for a vital f5 break. One player is violating chess principles by putting a knight on the rim, the other is carrying out a logical plan

No, great players never break opening principles or strategy principles (call them how you what). In this position form the classic variation of King's Indian:

White plays 9. b4!? because he doen't really have a good square for his dark-squared bishop. That means that White wants to hold his dark-squared bishop untill White can find a good square for it. Also the main ideas of this opening are:

1) White attacks at the Queen's side

2) Black attacks at the King's side

So White doesn't want to waste his time and starts to advance his pawns.

The move 9. Bg5 is a dubious move, because it helps Black to avance his King's side pawns by 9... h6!. Black attacks the bishop and gains a tempo.

Also the move 9. Be3 isn't a good one, because of 9... Ng4! - winning a tempo for playing 10... f5! next move.

Of course 9. Bd2? is a bad move - at d2 square the bishop doesn't have "a future" - he is really akwardly placed there.

The "principles" are the same for the every type of openings. But in a certain game one can "break" them "only visually", but technically he follows them:

Of course , you can!

There are variations where black and white players play like your strat!

Well, after "c6" from black, black simply dont stop white's queen side push,  cxd5 from black, cxd5 leads to free "c" file for white, black can counter play on "c" file but white has more space on white advanced pawn on d5, white is better to play. Or dxc6 leads to permanent backward  d6 pawn on "d"file.

White can play Ne1, Nd3 ,( cause you two tempo) and then "f4" give white nothing, exf4 by black free file for DSB and Kt post on "e5". Those variation has Ne1,Nd3,f3 only.

All moves have benefits and disadvantages, books have been written cos people had analyzed  those positions for decades(computer analyzed for millions of moves) and  they choose better variations in the books.

It takes months to years to build a strong opening repertoire but a well prepared opening can increase your elo up to +100.

The position he shown is typical of a KID pawn structure, black's chances lie in the f5-f4 break and white's chances lie in the c4-c5 break and put pressure on c7. You will end up learning this after looking through many games in this structure. White has more space on the queenside to put pieces on and a clear target on c7. Sure, white can attempt a pawn break with f4, but I don't think it will work out well in his favour, because he would create a target on e4 and a hole on e5 and he doesn't really have chance to create an attack there. Furthermore, he would strengthen black's bishop on g7 by opening the diagonal completely. I'm sure you can search chess databases in this line where white tried f4 push and see how they fare, I'm sure it's less successful than the c5 plan. Similarly, c6 by black will only serve to weaken d6 oncedxc6. It will only further hasten white's chance on the queenside and create holes and targets for white to attack in the centre. You can probably look up games where black tries to do this and see how they fare.

You should get Chessbase or some other chess database where you can research on games being played in a certain position or variation and see why some plans tried in the past don't work and why some do.

Opening principles are basic, generic, and exist mostly as guidelines to help beginners who don't yet know what they're doing. "Should I move my queen seven times in a row with no actual purpose in mind?" asks the beginner. "No", suggests the principles, "try developing a piece, instead!"

Once you get past that point, the needs of the position dictate what one should play, and principles don't really factor in anymore.

Looking at that KID game you cited, there are very clear ideas and purposes to the moves you questioned.

Given enough exposure to KID games, you'd start to see the common ideas, and those moves that look so confusing to you now will begin to make more sense. (Kasparov and Fischer are great places to start.)

Awesome explanation which helps clear away the fog.  Thanks!

In the Evan's Gambit, the position is wide open, with plenty of open lines. You need to get your pieces out quickly and your king to safety, or you will die!

In the Classic Kings Indian, the lines are closed and the pawn structures locked. You need to arrange for favorable pawn breaks in order to activate your pieces. If you quickly "develop" your minor pieces in front of your pawns, you will choke to death.!

Different structures, different principles take precedence. It's not that complicated

This game is exactly what I'm talking about!

Half those moves are pretty bad.

Starting with something basic, I'll point out that while f5 is a common pawn break, it's often prepared by covering g5 so there won't be any Ng5-e6 type ideas. In other words h6 is a common prep move for f5.

In any case, 1.Bg5 isn't terrible, but if your only reasoning is "connect the rooks" then you're playing like a beginner  Particularly in a closed position, there's no reason to rush to connect the rooks. For attacking the bishop is often good on c1 (maybe not so much in this position, but still), you can often save time by leaving it there for quite some time.

You can think of having more territory as has having a higher probability your pieces will find a useful job. It's directly related to piece activity. In all sorts of openings it's basic strategy to seek play where you have more territory and or more pieces. That's where the "attack in the direction your pawns point" rule of thumb comes from.

Great answer IMO.

Not only can a player's deep knowledge or experience lead them to play moves that look strange to others, but concrete calculation often has that effect too. Strong players do both, so sometimes their moves will be mysterious.

The given game feels like watching a car accident with the worst hang-over ever. Each time I become sick replaying it.