My introduction to gambling came on a family visit to my Uncle Bill. I was about 7 years old. It was Saturday, I had just received my $1.00 allowance (worth about $8.00 today adjusted for inflation).
Uncle Bill, who always had lots of fun stuff, broke out a mini slot-machine. He proceeded to demonstrate how it worked, then invited me to put in a dime (10% of my allowance). As I recall, I more or less took his suggestion at face value. Unsurprisingly, I lost my dime.
As I recall, I was reluctant to throw good money after bad, but he encouraged me to try again, probably to "win it back". Needless to say, I wound up feeding all 10 dimes into the mini-bandit, and finished in tears.
Kindly Uncle Bill proceeded to open the slot machine and return my allowance to me (or probably my allowance plus extra), while cautioning me that "Uncle Bill will do that, but nobody else will".
Fast-forward to adulthood, I have never had an interest in gambling. I'm guessing I would have gotten there no matter what, but I did always remember that lesson.