This is why I love my mechanic; it's a family-run joint co-owned by two brothers. My family has been taking our cars to him for years, and so has my girlfriend's (after I sang his praises enough.)

Having already won my parents' business, this is how he won mine once I could drive:

My SUV's A/C wasn't blowing at all. Called them, and they ordered a new assembly for a replacement. It would be a couple hundred dollars.

I take it in, drop it off, and go home; expecting to be waiting a day or two, as they're usually fairly busy.

I get a call an hour or two later; they'd taken it apart, and found a couple business cards blocking the main vent (yeah, I don't know.)

They put it back together, and since it worked, just charged me the two or three hours of labor.

They could have - without me knowing WHATSOEVER - replaced the whole thing, or claimed to have replaced it, and charged me the originally-quoted price.

If you're in the Bay Area (they're South BA,) please let me know and I'll give you their info.