Describe "nice shock"? Is that when your balls just tingle but your hair doesn't stand on end and no smoke comes out your ears?
Needless to say anything designed to deliver power can also store it in mass quantities, so best to learn first rather than tinker.
I think the most I'd want to do is replace a fan if it went out prematurely, but most PSUs have at least a 3yr warranty, and by then you've got a fair bit of cap aging.
Any repairs post warranty could turn into a money pit, unless it's a high quality PSU, but then those can last well beyond the warranty. I guess I'm saying it's more often moot than beneficial.