@hawkeye10,
I am young I guess, well 27 years young, however I remain to date a perpetual optimist despite spending a good few years to the contrary during my growing years. It may be down to the community within which I live, but in my experience putting others first (provided you have sturdy inner foundations) always reaps benefits. In my marriage we have a backwards mantra, which is that I look after her, and in return she looks after me, and we are both incredibly happy. For instance, I hate ironing, however my mother was a steamstress and therefore I am quite good at it, I do it because I do not want my dear one to have to as she hates it too, and it takes me a 3rd of the time.
It works with most people, however you have to be able to identify those that are merely exploiting your kindness, because there are a few out there that will drain you. If you select good people to be around you, and you look after them well, you get well looked after. It is a little trusting, and perhaps naive, but good people do gravitate towards kindness, Including a better calibre of men/women.
Look after people, and people look after you.