My dictionary defines "sentimental" as "marked or governed by feeling, sensibility, or emotional idealism"; it perhaps indicates just how sentimental I am that I cannot see exactly what that definition excludes.
I am sentimental. I am sentimental in trivial ways: I cry at the national anthem, or montages of the recently and heroically dead, I save letters and photos. I am sentimental in a more profound way: I ascribe emotional meaning to the world as it is presented to us, and, perhaps more importantly, I generally tend towards ascribing a kindly, or at least tender, emotional meaning to that world, when possible.
If you think of that line from "What A Wonderful World" that goes, "I see friends shaking hands, saying how do you do, they're really saying I love you" you will have a fairly precise understanding of what my brand of sentimentality involves.
Of course, you can't sustain that mood of kindly smoothing over all the time. When hungry or pissy or nervous that's not how I feel at all. And, of course, there's the mood of seemingly misplaced sentimentality: something that you felt sentimental about -- a job, a date, a place -- turns a different side of itself to you, and then you get the horrible feeling that maybe the sentimentality you viewed it with was a matter of falsifying the experience, a psychic airbrushing. And I don't, really, have any desire to live in a world of illusion, whatever the background music.
But it's all a little academic, thinking it through like this, because I have not ever been able to escape my sentimentality. My efforts to do so, to adopt a strictly realist view of the world, have only ever succeeded in acting as so much concealer for the sentimental zit underneath.
If I wanted to be mean-spirited about it, I guess I could see my sentimentality as a kind of emotional capitalism, where experience, stored away, gains interest in the form of a vague benign glow that covers the good times and bad times alike. I don't know. I'm going to take a stroll, and look up at the new moon, and think kindly thoughts about the world we live in.