Songs?

Lately I've decided to try to make more music. I've always enjoyed learning to play other people's art but I'd rather put my own contribution into the world. I often think of good one-liners that i think are neat but have a hard time putting them all together; or a hard time matching them with music (mostly from my guitar). Music generally comes really easy to me but doesn't generally stay on topic.
Anyways... the reason I started writing this: would it be alright to include a line in a song that seems to be a good, general, and fairly individual thought even if i don't necessarily believe it? A long time ago I wrote "expectations lead to disappointment so I hope for the best and live in the moment" and recently fit it into the chorus of a song. But since then I've learned that even though expectations often lead to disappointment, that disappointment from unexpected outcomes can teach the most valuable lessons ever learned. I'd rather expect greatness, tweak failures, and never give up, than to quit expecting and just enjoying whatever comes. Pleasure can come from living in the moment but true joy only comes with improvement from knowledge, which often comes from previous hardships.