Just yo raise some discussion, could this be a psychological related issues or is just a normal thing?
Also, have you come across such persons and what was your expression?
Until you have a one-on-one conversation with them, you shouldn't conclude that they derive pleasure from gambling even when they are losing. Yes it is a psychological issue(problem gambling).
My top three reasons why they keep gambling despite losing are:
1) They live in denial about being addicted to gambling. So they keep returning to the casino thinking they would win because they think they are in control.
2) They fail to realize that the odds are always against them. Maybe they already know this but just choose to ignore it and have blind faith that they could beat the system if they play more games.
3) They are just simply greedy.