The maxim is always that you should only gamble with money what you can spare, but most people know that. More importantly, keep a bankroll for gambling, and a strategy. And under no circumstances go over your limits, try to put your emotions aside. Only then can you enjoy it.
Your emotion is what makes you enjoy, so don't put it aside, instead, try to manage your emotion that you will not be too happy and too sad when gambling. Some just lose their control, when they are winning they like to win more, which resulted in them losing all their bankroll, but what's worse is when they are losing, they still keep gambling and forget their limit.