Air Circles of Perfection

I would like to know why air always forms bubbles. There is a bottle of hand sanitizer in front of me and it's gloppy liquid is interrupted from smoothness by little air bubbles. Some of them are tiny, like the top of a pin, and others are bigger, about one half of the size of a pen cap. But for the most part they are seemingly perfectly round. Are they true magical circles? Others are elongated into ovals. But why are those ones ovals and the others circles? I don't understand why air forms bubbles and not odd shapes, or why they don't just rise to the surface and disappear. It's pretty, but I don't understand the science behind it (and I'm sure there is some).