Being positive, for me, is often an ironic experience because I am not naturally an optimist.

same here. But I am using reverse method:
Every time I realise that situation is shit, I'm just imagining how can things go worse, much worse, like 140% bad =)
Believe me or not, the situation that I'm in, normally turns out to be really cool and I normally become happy that it's only this tiny bad that could happen =)