What was Demeters personality like?

Answer 1

Demeter was happy six mounts of the year; but when Pershone Demeter's daughter was with Hades for the other six mounts of the year, Demeter was mad, pittyless, painful (not to be messed with).

Answer 2

Kind and protective. She can best be imagined as a mother to all. But it wouldn't do to sadden her, as that might have a negative result on the fertility of your fields this year (or this century).
protective