I just had a bike built up by a (for now anonymous) local bike shop. They have a good reputation, but I've not used them before.
Took it out for the first time and found two problems:
1) The rear skewer was loose by almost a full turn – I discovered this as I pushed off; the wheel pulled into the stays and I ground to a halt. Good job I wasn't on my downhill start as this might not have happened immediately, but at 40mph in traffic.
2) The cassette had not been tightened. When I handed over the components, I told them I'd put it on by hand, but the mechanic said he'd make a note and that the bike would be tested anyway.
Needless to say, I was mad , but the shop is closed, so I fired off an email asking for an explanation.
Maybe they'll come back very apologetic, but how would you feel and what would you do in this situation?