Donatello is fascinated by technology. He spends a lot of time tinkering around with old gadgets. His inventions sometimes do, and sometimes don't work, and although he usually likes to learn from his mistakes, sometimes his brothers aren't so enthusiastic to try it again. If Donatello were being introduced to new people all the time, he would probably be quiet and shy. But since he has had, well his whole life, to get used to his brothers and Splinter they probably wouldn't view him as either because they are always being treated to his theological views. You can count on him to bring up both sides of an argument, even if you were trying to ignore one of them. He is usually quite amiable and expresses his emotions with a steady hand, until you get him into a debate. Donatello is a great debater, somehow managing to calmly turn both sides of the argument in his favor. Raphael also shares this talent, and their debates can last for days, until Raphael's fuse finally blows.