A proclivity is a tendency or an inclination. For example, I have a proclivity to eat cake and wear purple. So much so that I even did both at our wedding - which was a little over four years ago! Doesn't seem so long.
I was able to stand unaided, we were just pretending that even wearing heels I'm considerably shorter than Gary. Why we were doing that I have no idea. Perhaps we just have a proclivity to be daft?