I have a friend who had ONE geology class in university, majored in physical geography. But he is known as the rocks guy, since nobody knows what his major actually is.

I was on an island holiday recently, where the most prominent rock formation is simply called "the rock". I sent him one of these perspective trick photos where it locks like I'm licking 'the rock' with the message: "me, a real geologist".
He was mildly amused.