Hell, we don't even have to let anyone define optimism for us. It doesn't have to be the rah, rah, fake cheeriness variety. Usually that's just delusion.
Sometimes, the most optimistic people are the ones that seem least like it to everyone else. Too many people think Pollyannaism is optimism. Nope. Pollyannaism is delusion, too.
Your advice is the best way to get to real optimism. The kind that doesn't give a crap what anyone else thinks. Best way to define real optimism is when you can say "I got this..."
Good one. I'm going to color it up in highlighter. Sorry about that. :)