Could be a child (and in this case probably is) but I've known people like this as grown-ups too.

They just get really excited about the thing and want to have/do/whatever the thing and have absolutely no inhibition about using whatever method at their disposal to get it.

The rationality of the choice and the consequences just don't factor in - or are at least something their brain tells them is "a problem for later"

The original post made me think it's probably a teenager because they had internet access, but I can see how a younger child might think their parents wouldn't notice a charge. To a child, their parents usually pay with that card and never talk about it again. And because even young children have fairly unsupervised internet access nowadays (the post is from 2023), that sounds like a reasonable explanation to me.

I understand the "frustration" of wanting to buy something that you can only get online, but you don't have a bank account or anything. I was in pretty much the same situation as a teenager. When I was around 17 years old, I once ordered something and paid cash-on-delivery, but that's incredibly inconvenient. Using your parents' card can be incredibly tempting, which isn't an excuse to do it, but looking at it from this perspective, I can understand their motivation.

Haha my sister spent almost 500$ on the phone bill playing that dumb crane app where you actually operate a crane in Japan through your phone. And she did that shit 3 times just with 300 and then 400 the separate times.

At the same time she used her money to buy and sell characters, which included artwork of them. I have honestly no idea what that means but she wasted such money on this stupid shit.

i always forget bad people exist

I like this idea. Dude just gets art of his mom getting spitroasted. Last time he steals a credit card for sure.