My parents have always had the policy of, "if I didn't call you, I don't want it."
I didn't understand it as a kid (being told to hang up the phone a lot), but the policy has saved us all a lot of heartache and I've adopted it for myself.
- If you approach a random person on the street for help, etc, 99 times out of 100 they will be helpful or at least not malicious.
- If one out of the 100 people on the street approaches you, there's a decent chance they are that 1 in 100 people looking to take advantage of you.
Bad people are the exception, there are just a lot of people.