I have some relatives who lived through WW2 and were used to conserving things, they had to experience rationing here in the UK etc so they tended to be pretty stingy. They also saved everything, glass jars, tins, and anything that could be used to store stuff in. If someone lived through a tough time I would expect them to be wired a certain way by it.
Some people are influenced by parents to be stingy. I know a few people who always "have money" but hate spending it, because their parent would always be reminding them never to waste money.
But it doesn't always work that way. I grew up broke and I like eating nice food, buying expensive clothes and having nice things. I hate buying cheap furniture because it always just breaks, and better quality clothes tend to last longer too. I'm generally called a snob for it. But what it really comes down to is a childhood of eating and wearing crap, and the wilderness years 20-30 weren't much better, that now I like to enjoy quality stuff if I can get it. I'm also a person who likes buying people stuff. I'm generous with my money even though I never really had it for most of my life. So I don't know how that works. I don't like waste though, there are certain things I learned as a kid that I still stick religiously too - stuff like not wasting food, not just throwing good functional stuff away, etc. Deliberate waste was the closest thing to sin in our house.
I guess someone becomes overly stingy when their conservation makes them look irrational or mean. Like they have serious OCD about it.
