Optimism/pessimism are really weird descriptions to apply to the self outside of a therapeutic context. Given that they are both cognitive distortions or biases, as a cognitive agent, once you've noticed them, your responsibility is to root them out. But noting one and then clutching it tight as a badge of identity is little different in form from saying "I can't do arithmetic", with an implicit "yay for me!" rather than "but I'm trying to learn".