Learn to say "Don't Know"
If you don't know say don't know. That’s much better than doing some crap and covering up the issue. Recently my car had an issue of vibrating when the brakes are applied. In fact I haven't driven much in recent times and thought may be its some issue in brakes. As it is an old Toyota Camry, the wear & tear is expected. When I went and gave the vehicle for diagnosis to Midas service in my area they said it is something to do with brake rotors in the front wheel and they have to cut the rotor. Also the back tires have to be replaced to fix the issue permanently. I asked them how the tires are related to the issue, as I don't see anything when I drive and only when the brakes are applied the vibration occurs. They gave me a detail explanation which wasn’t convincing. So I told them to perform the brake rotor fix and not to do the tires replacement. They did the brake fix and when I came to take my car in the evening, I realized the issue wasn’t fixed. So I asked them why it wasn’t fixed. The fantastic customer handling person told me it was because of tires. I told them to explain how that is related to this, and then the chief mechanic came for rescue. He drove for a test drive and confirmed this is not any brake or tire issue, it is something to do in the transmission of the car where the gears are getting stuck when the car comes from high speed to low speed. I was convinced with this fact but was upset with the initial diagnosis. So went back to this super customer handling guy and asked him if you would have said this in the morning I could have saved what I payed you now. He was again again repeatedly saying there was an issue in the brakes too which was fixed. I again said when the problem is somewhere why I have to fix something which was working and pay for it. He never accepted because basically he was trying to cover up for the mistake. I again told him even if you couldn’t diagnosis the right issue, you could have simply said "I don’t know" & there is nothing wrong in it and I could have gone somewhere else. But never was he ready to take what I said and finally with frustration told him Thank you for your excellent service and diagnosis. I am very sure I will not go back there again; eventually they lost a customer which is not correct for business operation. Anyways I am just a pebble for them still I am one among similar customers whom they will continue losing if they are doing this in future. Crap!