Angel or devil?

So, you know how in cartoons, commercials, etc. they show someone with an angel sitting on one shoulder and a devil sitting on the other? The angel gives good advice, the devil, not so much. Well, apparently, I have an internal voice version going on. (That, or I'm slightly insane---which would probably put a crimp in any potential adoption, so let's go with onveractive imagination) Anyway, I've got something going on right now that has my two little voices engaged in battle. They're not really angel/devil, more optimist/pessimist. While I like Optimist's version of events much better, I find myself listening to and believing Pessimist's version more often. Now, I truly believe that good thoughts bring about good events and vice versa, so my question is.....short of expensive, long term therapy, a lobotomy, or copious amounts of alcohol (none of which sound very appealing), anyone have any ideas for getting Pessimist to shut up?