What are the most common squares to be overworked? 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.