Castle vs light/dark bishop


Castling to one side or the other doesn't really have an effect on the enemy bishop's performance, so let me try to give different criteria and then use it to answer your question.
The most common ways for a bishop (and other pieces) to be attacking is:
1) attacking a weak enemy pawn
2) assisting in checkmate
(attacking non-pawns is possible too of course, but weak pieces can run away easier than pawns and kings can, so we'll use these for my examples)
So here's some basic examples to illustrate these two
But in real positions there are other elements at play too, so it would help if you posted a game of yours that made you think of this question.