I would definitely consider myself an optimist, mainly because I don't see much point in being anything else. I don't think being optimistic means that you naively assume the best, no matter the odds or evidence showing otherwise. I think being optimistic is a decision that you make every day. It forces you to be creative and never stop searching for a solution to whatever problem you're facing. It gives you the ability to see what you have, in its entirety: life will give you the cynical view. You don't need to search for that. Optimism gives you the positive side. Sometimes, the only positive thing is that maybe you can help others. Sometimes, the only positive thing is a lesson learned the hard way; but those lessons are often the most valued.
I'm not saying that everything in life is wonderful or something to smile about. There are far too many things that are pure misery and hopelessness. But by choosing optimism, you are choosing to put one foot in front of the other and keep going. Far from making you a silly do-gooder, it makes you resilient. You have to chug along on the belief that things will get better. Even when things get worse before they get better.
Everyone has peaks and valleys in their emotional state, and some seem more extreme or prolonged than others. Overall I'd say I am happy, perhaps a little anxiety-prone. Highly-strung, as someone once called me. They further elaborated, "There are greyhounds, there are thoroughbred horses, and there are people like you." But over the years I've been able to learn to moderate these extremes and gain control over myself. Instead of hitting the panic button the instant something doesn't seem to be going the way I'd expected, I can now calmly rationalize and think and work out the best course of action. Not 100% of the time...obviously. But when faced with a challenge, I tend to consider there must be a way.
Being able to calmly work out a resolution is a thousand times easier when it's someone else's problem. You're not as emotionally involved. But you get the most practise working out your own problems, and it's better that way anyway. I'm a work in progress, like everyone else on the planet.
One of my favourite little thoughts is the saying "plan for the worst, but hope for the best." It's helped me avoid disappointment just in the act of being prepared. It's a different way of considering what is the worst thing that could possibly happen. Sometimes when you think of things that way, you realise they are often not all that bad. You think, well, if that's the worst case, I can probably deal with that. But at the same time you are also keeping the glimmer of hope that things might turn out wonderfully, or at least not-bad.
So really, when you consider it that way, doesn't it just make sense to be optimistic? Doesn't pessimism seem like a gigantic waste of time and energy? Not only are you looking for the worst in every situation, you're likely to find it and that will obviously have a negative effect on your attitude and overall mood. You won't be looking for the solutions: you're giving up before you even start. I know which choice I'd prefer to make.