What you do every day matters more than what you do every once in a while. Read The Power of Habit.
Sometimes people don't notice the things others do for them until they stop doing them.
Love and appreciate your parents. We are often so busy growing up; we forget they are also growing old.
Never do something permanently foolish just because you are temporarily upset.
Habits, good or bad, can always be traced back to your own thinking.
Whatever you fill your brain with and whoever you spend your time with... will determine your life a decade from now.