Fear is stupid. You miss out because of fear. Regrets are too. Because regret means you wished something hadn't happened. But it happening gave you an experience you learned from - an experience that is now shaping you. Regret is dumb - so is fear.
It's easy to accept what someone gives you without acknowledging it. Don't be the person who accepts it without a thank you - from the heart - from your soul. Be the person that looks that person in the eye and sincerely thanks them. Because they don't need to do it. Yet they do - without thanks. Give it back to them. Not because you owe it to them but because you truly realize the value of what that gives you.
Don't let life harden you. Don't let what happens put up walls - or make you distrust people. Always believe there is beauty in the people and the world. Putting up walls and keeping away from the world means missing the beauty that is there - the beauty of people and the beauty of life. Don't lose the lesson, but don't harden yourself against the rest of experience.