I think the main reason why people needs and prefer to gamble because they want an easy to get earnings, less efforts and time.
I can't disagree on this, when I gamble that's the only thing that I'm thinking. I have to win, with less effort and time. I want it the fastest way and that's my mindset, you can't blame me since I have won some good amount before and it stick to my mind that it can happen again.
In gambling people tend to satisfy their earnings from gambling even they take risk out of it.
That risk is worth it when you taste the fruit of winning but it will be sad and regretful when you lose.