What's the most frequentlyl mis-played opening by amateurs?

An opening that was misplayed by both my opponent and me ... I once played the black side of this French Advance at an OTB tournament. I still perform ritual self-floggings at the anniversaries of this event b/c I missed 5. ... Qa5+ ...

I could beat Kramik with Black after 1. e4  e5 2. Nf3  Nc6  3. c3  d5

4. Bb5??

black side of 2 Knights variation - fegatello and it's not even close.

French Exchange variation: Alot of players Just sorta move around waiting for the draw to come and play very inaccurate and lose.

Maybe Kramik, but defenitely not Kramnik. 

With that opening variation I could beat both Kramik and Kramnik!

Sorry, no way. I could manage a draw against you with white pieces. What's so bad in it? Do you lose a queen in forced 20 moves?

You already posted it 4 hours ago. 

Hi, MSC157 I am old and somewhat senile so hesitate to say this but I do not think you could manage a draw against me with the white pieces from that position.

OK, I've just read your description, so I'm sure now I would not manage a draw :)

But I still think Kramnik would win with white pieces (standard time control, not correspondence).

This is my submission since I've seen white play this no matter what opening black uses!

Primary example:

Example of white ignoring my opening #1 (from a real game):

Example #2 of white ignoring black.  I've seen this many times.

"White abandon's the game"  Oops!  I bet that some people don't see why that's a mistake and then some are pulling their hair out because of it.  :-p

I've done that a few times, and everytime I do I kick myself for it.  It's a bad move on white's part to try to trade their good bishop off.  In the French Defense, white's king's bishop is very powerful, especially since black's queen's bishop is stuck.

You see 3...Bg4 in the philidor from 1800 players?  I need to play chess in your area, I'd be rated 2200 in no time...

Hi MSC157. With this position 1. e4  e5  2. Nf3  Nc6  3. c3  d5  4. Bb5  I could beat Kramnik [or anybody] in correspondence chess. In over the board timed chess--it would be close call either way. I could memorize the variations [this would take a while] and If I could do that--my chances would be superior.

It is an opening variation I have studied extensively--at first I thought it was a draw but then someone came out with a win for

black in one of the main lines and I came out with ideas for Black in the other lines.  It is a weird postion because if you just look at the position one would never guess it is theoretically losing for White.

Grandmasters have played 4. Bb5? 

Here is another line which if you look at vote chess it has been played more than 4000 times. And to top it off the correct continuations have almost never been given.

I would say that most players have no idea what they are doing when they play the St. George defense which has some very deep strategic ideas.

Oh, not 1800 OTB, but 1800s on chess.com seem to play it quite frequently against me.

Oh, ok, thank God