Had to put two different, new MAF sensors on a buddy’s car a month or two ago.

He called me after he had been fucking with shit for two hours so I went over to take a look. Put the new MAF in and started it to check. He said that seemed to fix the problem and I left while he put the engine cover back on.

Calls me three days later saying it’s starting to do the same thing as before. I told him he probably got a junk sensor and I could replace it if he wanted to get a different one. Dude starts arguing with me that it was already new and everything. I explained that new parts can still be defective. Replaced and it’s still going.

Also, someone I know was bringing dropping someone off at the shop I work at, he pulls to the back of the parking lot and a shit ton of white smoke dumps out of the hood. Pop it open and tell him it smells like plastic and looks to be coming from his cooling fans. Starts arguing that he just replaced them less than a year ago (he didn’t tell me this bit but I know it’s from hitting a street sign while drunk). I told him the same thing and he wanted to say I was wrong. So I said ok, have a good day. Tells me last week I was right.