Damn idiots in class

I don't claim to be an expert in auto repair, but I know enough to figure who is a fucking idiot and who knows their stuff well. I hate it when these fucking idiots in class start tinkering around my car without my consent. I don't mind helpers, but I hate unsolicited help from people who are likely to do more harm to my car than me.

1. There's always a guy who always floats between various groups in the class. He helps a little bit, but always disappears when it's time for cleanup. He also liked fixing other people's car without their person or presence. He replaced a PCV valve on another guy's car when the owner briefly stepped away. The owner wanted to do it by himself. In another case, he broke the spark plugs or wires on another car. I gave him the evil eye to keep him away from my car.

2. This old guy in another class came to watch me do an alternator test. He had some strong ideas on the direction of current measured by the VAT-40. I politely disagreed with him and tried to ignore him. But the old fart didn't take the hint. Instead he started probing around my car. I told him to stop and go away.