With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion.This has always been my single largest concern about organized religion. As soon as you let someone else start thinking for you - especially about something as important as religion - there's trouble. Religion (and there's a very strong case for putting patriotism in the same category) is used to justify some pretty awful stuff that people would normally never do, but they are reassured - nay, required! - to do them in the name of their god.
My greatest challenge as a rabbi and as an active member in my faith is to encourage the spiritual development of others and help them find their answers without giving them answers. To teach them that following the law can never get in the way of being a good person. To live in a way that encourages those around me to strive constantly outward, allowing their hearts and minds to stretch and grow and always stay open.