This will be a compilation of things I will say during my graduation speech, if I ever graduate :)

I am a person who handles things clearly.
1) If a sorry needs to be said then it has to be said. I do not go around treating the person nice without admitting that I made a mistake and am sorry.
2) If a thank you needs to be said than I will say it. I try not take appreciation for granted (My hubby helps me to improve on this). Sometimes you might find me saying thank you to little things but for me, if it needs to be said then it should be said.
3) If an explaination is needed then I will explain or clear it up... (ok when I remembers).

However, this is not the norm in the place where I am xxxxxxx right now.
1) Mistakes are done - without people admitting to it. People just assume that if things are not that bad then it's ok. Worse still, sometimes you are being given the blame as if you did something wrong, when the fact is the other person forgot about it!
2) Thank you is not a common thing here... there are only a few colleagues who remember thank yous. It is like, you are suppose to help me or remind me anyway this is your responsibility, so thank you is not part of the package. There was one colleague who always remember to give word of appreciation and encouragement but he left. My ex-boss in Motorola, is an encourager. He helps you to build your confidence in handling matter. "You did a good job" is such an affirmation.
3) Here... when your emails are not being replied, you know you should just drop the matter. Nothing definite will be explain and it is "a common understanding" that this is a sign for "I do not have time to talk about it. So let's drop this topic."

During my graduation speech (if I graduate) I will mention:
1) Say sorry when you make a mistake be it big or small. Be it to your boss, senior, colleagues, juniors or even your students!
2) Say thank you and give words of appreciation whenever possible.
3) Say you don't have the answer if you do not know instead of just keep quiet and leave others wondering and do not ASSUME (making an ASS out of U and ME)!