I see PC purist complain about their cooling so much.

https://sh.itjust.works/post/56904751

I did that once in one build.

It was a shitty PC that I kept upgrading, but for some reason kept the case. so when it kept overheating,I just put a box fan just like that

How well did it work?

100%

of course it did.

it looked like shit, but it worked.

Did you put an air filter or did you clean all the dust every month or two like I did?

lol, were do you live? it got a wee dusty after a year but not even close to that,
Lol, I just found the pic online. I basically just used canned air every 2 months and gave it a quick pass on the heat sinks and any possible dust bunnies. Nothing near as bad as the pic.