The words "Thank you!" are not said enough. If someone does anything for you, literally anything, say, "Thank you!"
You are going to hurt their feelings by saying it. If you don't say it you're looking at 50/50 odds of hurting them. Just say it, what do you have to lose?
Life Lessons are quick bits of real life that I feel should be public service announcements. Have one to hare? Leave it in the comments.
Life Lesson 1, 2, 3