It's a sign of submission, thus making the person being begged to feel dominant and superior. These individuals feel as if they're in power when you beg, because of said submission from the person begging. From a psychological standpoint, this reinforces a dopamine-controlled response in their brain to make them feel good when they're in control (as is in most superiority complexes and the like), and thus, the feeling of being in control and in power feels good to them--and as such, so does getting people to beg.
As do I. Not only do I think that OS is a hard-wired orientation much like any other orientation is, but also, I choose to be OS and I don't want to change it. Humans are just plain icky and mean :I
because it makes them feel empowered.
No they don't.