Don't go making an ass of anyone, now--
Mechanics are only people, independents even moreso than factory-trained folks. These people do not live with these members of our family and the cars themselves can't talk, but rather just sort of hint at what is wrong-- making a mechanic even less apt to get the diagnosis correct on the first attempt.
Imagine you're a flustered parent of a mute child that can't use sign language. Now imagine your mechanic is a doctor going only on parental diagnosis and the pointing finger of the hurt child. Easy fix, right..
I had problems with the leon when he was new, whenever it was cold the car would sputter and stall *only* on the first cold start of the day-- the dealership never fixed it and it hasn't gotten better or worse over the course of 9 years-- I like to pretend he is just a hard sleeper
Kudos for getting it right-- that is one of those things that would drive me mad and I would never find on my own-- I'm from the "throw parts at it until it stops doing whatever it is that isn't right" school of mechanic'n