You keep it all in.

There are those things that you just can't tell, without committing yourself to a certain direction forever. People keep their thinking on subjects like politics and religion quiet, because people feel so strongly about those things that you might make an enemy of someone whom you enjoy a mutually beneficial relationship.  But what if you feel that people shouldn't care so strongly about anything that they it would prevent them from getting along with someone that has opposing views? You keep it all in.