Positional game
Are you kidding? I know tons of games where you make a plan, and then forget what you were ever thinking because you end up too occupied sifting through tactics till an endgame comes. It's possible to plan some deep penetration along the open b file, then your opponent plays some move, 5 moves later there's a pawn on b6.
Very funny. In fact by no means does that have to be the case. In a predominantly tactical game a plan often has to be exploited by tactical means, and sometimes there are so many tactics that the resulting position changes drastically (and you may forget what your original idea was!); and that can happen with a good or bad plan! I mean the whole point of having a strong position is so that tactics are more likely to favor you, so that when you or your opponent initiate them, it works out.
Going back to the example, I'd be happy if my plan forced my opponent to make some tactics (to avoid passively losing the b file) and lose some random pawn just so that he can block my plan with a pawn on b6.