1) I saw a "mechanic" try to remove the decoration bolts on the hub cap of my car instead of removing the hub cap then removing real bolts on the wheel.
2) The oil filter on my car fell off on the highway a few minutes after a "mechanic" changed the oil and filter.
You're not the only one who has seen that. Some years ago I worked as a copier repair tech and I was on a service call to one of our local auto shops. While fixing their machine I saw a mechanics certification plaque with the name of one of my buddies on their wall listing his as their top certified tech with all of their other apprentice techs certificates under his. As far as apprentice certification went basically if you spun wrenches their for more than 90 days without getting fired you got an automatic certificate plaque stating you were an apprentice tech.
Thing was he had not worked there for at least five years and had left due to disagreements about proper job conduct, practices and having to be in charge of a shop full of untrained idiots.