As I look back at some of my writing, I'm acutely aware of sounding naive or overly sentimental. I'd like to share some thoughts about this. In particular, I'd like to sketch the progression from naive, to cynical, to post-cynical as orientations to reality. 
Consider the abstraction of "the total possibility space". This is the domain of all possible actions/events/circumstances. Some of these are warm and fuzzy and inspiring and make us feel uplifted. Others are grotesque, evil, enraging, and terrifying. Right now, there are events unfolding in both of these possibility spaces.
A naive person has ideals and is optimistic, but maintains this position by ignoring/avoiding/denying the horrific stuff that humanity is capable of. They may be aware of it as an abstraction, "some people are bad" or something. Or, "there have been wars in the past and a lot of people died violently". But these are abstractions and the weight and truth of them are not experienced by the naive person.
A cynical person sees this horrific stuff and says, "it's a dark, dangerous world and all hopes of goodness are naive and childish". They incorrectly assume that just because there are horrible things, the beautiful things don't count. This is a bit like watching a children's movie in which the bad guy wins at the end and then staying in that mood for the rest of your life. It's the "if you can't beat em' join em'" response to life's disappointments.
The post-cynical person sees both, and commits themself to realizing the life-affirming outcomes in the total possibility space. They don't delude themselves into thinking that all is beautiful, but they devote whatever degree of agency they have to bringing about a better world. As I shared in a previous piece, "All things aren't shining, but all the shining things are."
I am generally an optimistic person. However I'm not generally naive. I'm painfully aware of the tragedy of living. 
People get stuck when they over-identify with one stance and deny the other.
 Daniel Schmachtenberger has spoken about the progression from naive, to cynical, to post-cynical. I'm paraphrasing and adding my own points of view here.
 If I were to self-assess, I think I still spend time naive and cynical in a kind of back and forth. This is to be expected because it is a dialectical process, and the tension that I feel with neither stance being completely true creates the conflict necessary for the higher-order, more complete post-cynical stance to arise. See David Chapman's book/website Meaningness for a discussion of 'stances'.