I did physics, and when it was revealed it often got a sort of "impressed" response, which I think shows how misunderstood it is by many.
When I tell people I do Geology I get one of these:
1. "Isn't that the study of rocks ? What can you do with that"?
2. "Oh, like what Ross does on Friends"?
3. "...Geology Rocks"!
4. "Oh! Oh! I know about Geology! Sedimentary, Igneous and Metamorphic"!
The only difference between you and me is I don't find it funny when I hear it because i've heard it all so many times i've lost count. What's worse is there's not good replies to them.
1. Well quite a lot actually, since the study of rocks is the study of earth resources I can get into the oil industry, groundwater industry or even the mineral exploitation industry which....(by this point they just have a blank expression on their face and no longer care).
2. Not really, Ross specializes in palaentology (at which point they interupt with "Oh like Dinosaurs"?!). Then I have to reply with "Well, we don't really do much on dinosaurs, it's more microfossils like trilobites, graptolites and bivalves, or studying the past climate in order to create models so that....(by this point, they have lost interest).
3. ....Did it ever occur to you that i'd have heard that joke loads of times before so won't find it funny now ?
4. There's more to it than that, but I really can't be bothered to explain it.
Annoyingly I can no longer just use the "it's the study of earthquakes, volcanoes, fossils and oil" excuse as when I start the masters in engineering geology it's not something that can be summed up in a single sentence.
So far all I have prepared is "..It's basically just like Civil Engineering", and if they don't know what that is, i'll just point them to the nearest Google search engine.
I study psychology and almost laugh to myself before mentioning this, simply because I know full well that they will respond by saying something along the lines of; "Oooh, don't figure me out!", "better watch what I say around you then, eh!"
I think the best reply I got after saying I was going to do pharmacy was...
"What? You're going to work on a farm?!"