That is a natural reaction to what happened, Obi-Wan. When we're hurt that deeply, we get angry. Were you not in pain, then you'd be something entirely unlike other men. A stone.

[It proves you're human]

The Jedi of my time are probably not quite the paragons of self control that yours were. I admit, many of us do channel our anger towards constructive ends, much like Master Windu did in yours.