If I've got any responsibility for the management of a project (and that includes putting tickets in an issue tracking system and resolving them), I ask the question of "What happens if we miss this deadline?"

I usually ask this question at least once a week, when the subject of the deadline comes up at the meeting.

There really are some things where, if you don't do something by a certain time, you might as well not do it at all (say, a grant application.) On the other hand, I was involved in a project that ran three months late, but somehow we managed to have meetings with the client where we always agreed we were a week behind schedule, but that everything was cool. The customer was very satisfied by that project, however, my continued involvement was expensive for my firm.