Ive been in this debate before ,it really depends on the mechanic and the customer ,just because you have a certificat on the wall dont mean your always correct and or treat customers properly ,some over charge ,its like any buisness out there you will get a couple bad apples in the barrel theres no disputing that fact ,as well as bad customers as well ,im sure more than a couple customers are idiots for sure and blame mechanics for there hamburger at mcdonalds being made inncorect ,lol ,,im a professional my self with a wall of certificats but i make mistakes still ,,its the human factor