Generally are there any distinguishable patterns you look find in the opening that you recognize as weak, or exploitable. Or generally any openings that provide the over-bearing sense of duty on a piece?
Prior to castling, f2/f7 are the most exploitable squares in the game, because they are defended by only one piece: the king. That's why so many king-stuck-in-the-center games are rounded off by a piece sacrificing itself on those squares.
On the queenside, the c2 and c7 squares also have problems, because of a tactical sequence like this:
1. Bf1-b5+ Qb6xb5 2. Nd5-c7 (forking the queen with either a king on e8, or a rook on a8)
But these tactics happen less often than tactics on f2-f7, because the queen is usually a better defender than the king.
In the French Defense, Tarrash variation, `1.e4,e6 2.d4,d5 3.Nd2, Nf6 4.e5,Nfd7 White must carefully guard d4 and e5 as Black will play c5, & Nc6, & possibly Qb6. One scheme for White is Bd3 & Ndf3 & Ne2 & c3 (not necessarily in that order) & be willing to play ef6 if Black plays f6 (which can result in a weak Black pawn on e6).