All of my knowledge is useful for me. However, trying to bring up stuff that I know in everyday conversations is a bit difficult, because ordinary people and I don't really share the same interests.
Satellite communications ..... ummm, no....
The Roman Empire ...... ummmm, no....
Music Production ....... ummmm, no.....
DJing ....... ummmm, no....
Astrophysics ......... ummmmmm, no.....
Marketing ....... ummmmm, no.....
Sex ...... ummmmm, yeah, but you can't bring that up into everyday conversations without serious awkwardness.
Somebody get me a hobby or point of interest that other people can actually find interesting, please?