Anybody got a flamethrower? (No, put me down!)
I realize this is one of those "you don't know how much work something takes until you actually do it" things, but right now I want to kill each and every one of our little darlin's. You may think a little itty bitty last-minute change is no big deal, but you'd be wrong - you set into motion a long chain of events because I have to go back and fix/change/correct everything I've already done for each one of your little whoopsies.
This is why I have a headache and my legs are numb - I'm trying to squeeze all these changes in now BEFORE you little bastards make me go back and do ten times the work when you fuck up.
(It also doesn't help that other departments involved in the particular process I'm working on didn't think things through very well - or, more to the point, didn't solicit the opinion of the person who actually does this stuff, i.e., ME - so now the end processes are FUBAR and I'm the one having to deal with the mess.)