Few from my end -
1. Do not allow any one (including my wifee) to adjust settings on my HU. I hate people who directly touch my deck.
2. If my travel is more than 5+ Kms & that too very needed then only I will use my car else prefer 2 wheeler
3. Maintain records of service & petrol along with minute details. Like kms/ which petrol pump what rates etc etc
Addition to above once I had a good big mess with a mechanic. I had washed & wax my car & was near this garage. He came with his dirty hands touched the bonnet to feel the smoothness. But he forgot that his hands is full of greese & same was marked on my fresh bonnet. I showed him the real anger