A character with a Chaotic alignment doesn’t necessarily live his life by choosing to spread random acts of chaos. Instead, a character with a Chaotic alignment lives his life in such a way as to find codes of conduct stifling. He doesn’t follow any specific pattern and refuses to, because they get in his way of living how he wants. Spreading random acts of chaos, though a Chaotic act, would most likely lead to his being uncomfortable, imprisoned or dead, and none of those things generally appeal to most people.
My sorcerer is feeling bored. Looking around the town, he chooses not to throw fireballs at the orphanage (prison time and execution are two things he generally tries to avoid), he chooses to stay away from the whorehouse (last time he was there, he came away with the most DREADFUL rash… took the clerics six weeks to get it cleaned up!), and the last time he went gambling… well, let’s just say everyone started calling him One-Eye after that… no, no, performing some civic duties sound like the best option. Especially since that card shark, Calimen, has a bounty on his head…