Well her profile says she 'thinks the opposite of what others think, likes what others hate, and hates herself when she makes others happy'.
The opposite should hold true, she is happy when she makes others sad, and, well, most people hate... wait.
If she likes what others hate, couldn't make make her a Masochist too 0_o
OK thinking about what Seija likes and dislikes just makes your head hurt.
Ultimately, of course, Seija is a completely screwed up character that is probobly literally impossible to get along with. Especially since she likes being shunned [Because most others hate it]