Thoroughbreds are often hot tempered. notice how i said OFTEN. not always.
i would like the say this:
if you are going to own a thoroughbred, i would suggest you have experience with the breed. whether that means a friend having one, a trainer, or you just doing research. You could read books, look it up, and meet some thoroughbreds in person. People who don't have experience with a breed they are wishing for (in this case, the thoroughbred) shouldn't buy them without researching. Thoroughbreds can be great horses, with a person who knows how to take care of them. you don't want yourself to get hurt and you want a thoroughbred to be with the right owner! :)
So all in all, i would research thoroughbreds before buying one if i were you.
http://www.horses-and-ponies.com/breeds/thoroughbred.shtml
http://horses.about.com/od/breeds/p/thoroughbred.htm
http://en.wikipedia.org/wiki/Thoroughbred
Happy Trails!