i know it's not really a positive world view, but if you just keep repeating to yourself "people are stupid", you'll find that you're occasionally surprised, rather than constantly disappointed
I lucked at my local NAPA. There's a guy there that will bend over backwards to find you what you need, and doesn't care how much time it takes to find. Those guys are a rare commodity. I can't count how many times i've gone looking for something at a different local parts store and just walked out shaking my head.