My spam FOLDER in Gmail has about 1000 items in it on any given day.
My inbox has zero.
Every once in a while I get a series of emails that fool Gmail's filters, and after reporting them for a while (like thousands of other users do), they'll disappear. Those "once in a whiles" get fewer and farther between.
I lose a few real emails into the spam filter as well - but mostly because I moved to contracting, and I get genuine contacts from foreign recruiters - and they're barely distinguishable from spam by humans. I just have to know to take a peek into my spam box after submitting applications.