a "little" birthday goes a long way

Today was one of my co-worker's 50th birthday. I planned this surprise lunch at an all-you-can-eat buffet where the birthday person eats for free. The plan went off without a hitch, and it was a good time.
But all of this surprises me somewhat, seeing as who I am and the fact that I haven't always gotten along with this person. However, these kinds of things seem to build the relationship - doing things for others, just because. And going out of my way to engage in these kinds of things takes me way out of my comfort zone. My natural reaction to this kind of talk is puke!
Could it be that I am changing the facet of my very being? Whoa there... let's not get carried away just yet!