Why eat tasty food, drink alcohol, have sex? Why do anything that makes you feel good? And hopefully I don't have to actually answer those questions for you. Too much of anything is always going to be bad, but life is full of simple pleasures readily enjoyed in moderation without being detrimental to your health or society. The question isn't why, it's why not? If you're driving or working then that's a good reason why not, but if you're on your off time with no pressing responsibilities and not operating heavy machinery then again, the question is why not? It's fun and it doesn't hurt anyone. Enough said.