I wish I had your problem. I have no trouble telling people it's not fixed right. I want to be friends with my LBS because the guy at the counter is SO cute!

When I had my bike built last year, I rode it for a while and kept hearing this weird jingling sound when going over bumps. I eventually narrowed it down to the cassette on the back. I took the rear wheel off and told the LBS guy (different shop in a different city than the one I am stalking now) that something was wrong with the cassette. Got the wheel back later that day and he said everything was fine.

Rode the bike, cassette still making that annoying noise.

Take the wheel back and told him the cassette is making that noise again. He told me it must be something else I'm hearing as he didn't find a problem last time. I take the wheel and bounce it up and down in front of him - jingling on every impact. Sure enough , when they built my rear wheel, a spacer was forgotten. I got him to replace the cassette and everything at no charge to me (they should have done it right the first time!).

I had a great relationship with that shop, I think this incident helped. They saw me as someone knowledgeable and demanding of the best service. Any question I had they'd help me with and anything I wanted or needed they'd order for me. I don't think he stiffed me on purpose the first time, but after that I know they were extra careful! I used to buy them pizza and we'd sit around and shoot the breeze too. It was great. I want cute new shop guy to be like that, haha.