I don’t think people are pleased with bad exeperiences and I think bad experiences don’t please a pessimist any more than an optimist. I don’t agree with the explanation that the pessimist is pleased with bad experiences because they prove him right, because I don’t think a pessimist wants to be proven right in the first place. In fact, the opposite is true. The pessimist is using pessimism as a defense mechanism and in fact hoping he is wrong so he’ll feel better about reality and the outcome once proven wrong. The pessimist is bracing for the worst, hoping things will not be as bad as expected and he‘ll feel better. So, I think the direct opposite of what you said it true.