R is not a shy, retiring child. I will always remember R being teased by two older boys (maybe two years older?) on the playground. Her response was to start slinging insults back--"Well, you're stupid!"--in a completely unfazed, undaunted sort of way until they retreated from her back to the safety of their parents (who burst into laughter at R's chutzpah). At her age, I would have cried and been traumatized for the rest of the day.
One of her favorite alter egos is that of a "fighter pup". She pretends she's a dog named Roxie (I don't know where she got the name, she came up with it herself), who defends the "babies" and animals against bad guys. Roxie is ready for action, with a wriggling tail (R's leg, which she will hold up in the air as she crawls around on all fours) that has a tendency to kick/smash people and things.
In general, R isn't especially aggressive, but if another kid starts something, she will definitely respond in kind, even if that includes a physical altercation. She is definitely feisty, ready to stick up for herself at all times (it always surprises me how ready she is to ask strangers for things she needs). Usually this is good, but sometimes it is expressed in less-than-desirable ways, like pushing other kids out of the way if she wants something.
Based on her personality, I thought she would enjoy tae kwon do, as a way to positively express her more aggressive impulses. So I signed her up for several months of classes. She liked it at first, but it turned out to be too structured (and involve too much disciplined waiting) for R at this point. Maybe we will try again in a few years. Watching her in her little uniform was pretty darling though.