Plus it makes me feel great knowing I'm contributing to reuse and giving money to a company that helps employee less fortunate people.
Still, I occasionally find some decent stuff and I still hit up the Goodwill anytime I'm out running errands and pass near one. It's just a matter of luck so the more often I look, the better my odds.
I tend to have less luck with the common stuff like nice wool pants or well-fitting button down shirts but I've gotten some really nice jackets and at three pairs of Allen Edmonds shoes ($250-350 MSRP) for $20-25 each with only a cleanup and polish needed.
It's nice because even though I'm still buying the occasional $20-40 shirt, I've got a few pairs of shoes that are much nicer than anything I'd be able to justify buying at retail.
Many people born poor, now take perverse pride in procuring sneakers they didn't get as a kid, and collect them, often at a high cost. Staying 'clean' in a dirty area is almost always a popular signifier of 'class'.