I see stereotypical so-called positive thinking (it isn't raining, I see rainbows and butterflies!! The puddles and wetness aren't happening!!) as a form of denial so people can function for a little while. I don't think it's very useful beyond about five minutes! Surely a better way is realism (yes, today does in fact suck badly) along with applied optimism (it sucks but there has to be a way to improve this situation, I believe I can do that ...), and looking for real positives (today sucks, yesterday sucked, but last month was okay and maybe tomorrow can be also).