The most important things I've learned from my career history:
1) Never, ever, ever trust an ATM. Save your receipts.
2) Never, ever, ever trust the data on a directory site like Yelp or TripAdvisor. Do your own research.
3) Never, ever, ever trust anyone representing a temp agency. Corruption is rampant.
4) Never, ever, ever trust a right-wing construction contractor who tells you he doesn't employ any "illegals."
5) Never, ever, ever trust any system that exists for its own profit.