Pet peeve 74: whenever I slip and focus on complaining about who and what instead of thinking about how and why to solve the problem. This is doubly frustrating because I enjoy solving puzzles (i.e. problems) more than I enjoy annoying people.
It's so, so easy to kvetch. It feels good. But, it's more productive to figure out why the problem happened and how to solve it (or break the problem down to solvable subproblems).
Being human: it's tricky.