Grow up... ok. I say that from the perspective of a guy who moonlights as a mechanic when possible.

Stuff happens in life and it does suck. Frequently though. It's not your mechanic building the trans. He takes it out, brings it to another place or guy and that guy is the one actually doing the rebuilding. Meanwhile..lemme tell you, the mechanic loses money each time he has to touch the trans. Therefore he wants it to be right the first time. Extra time spent on your car means he loses money on the next car in line.

That mechanic wants you to be happy and satisfied. If you think it's a pain to go back, it's worse from his end. Bad repuation to anyone you talk with about the experience. Lost money because time is money in that business Etc etc. Go back and be a good guy. Yell or get angry only if need be. Like I said.....you didn't like the answer from guy X. So go in and ask to talk to the guy that runs the shop or the owner. He's got a direct interest in you being taken care of properly.