I started gambling in 2016. Back then I was exploring the forum and taking part in discussions. I started paying attention to the gambling section and trying out some websites. I think my first experience was playing dice on Primedice. I did not invest any money, kept using the faucet and using various approaches to make something of it. I think I won around 40k satoshis there. Then I slowly started experimenting on other websites with different games, like crash and slots.
I believe this answers all of the questions you've asked in your post. For me, gambling was and still is a field of experimentation, a way to get nice emotions and to have fun.