I feel pretty much the same way - I'm ok at some science, bit of maths, bit of this and that, but prefer to write things that are just (at least to me) amusing.

At first I cared that people might be interested in what I write, now I just write about the surreal experiences of my everyday life (in software engineering) and things that I worry about so much about that they make me wake up in the morning with a cold sweat.

Catharsis, it's a great reason to keep going imho.