My statistics professor was banned from every casino in Reno for counting cards.
She told us that she won something like $30,000 playing blackjack. Unfortunately, she hit up three casinos in a row. Casinos talk to each other, and she was very firmly asked to never come back. She got to keep the money, though, so hooray for math.
Remember, when people tell you that they don't need to learn higher math because "they will never use it," all they are saying is they are not inventive enough to make use of practical knowledge. Stay in school, kids! (Or learn it on your own.)
I remember doing something as simple as keeping track of all the cards in a simple game of
Rook. I won every hand, but it was pretty mentally draining. I also didn't make any friends at that table, and I was playing against my family.
If you've learned a skill, use it.