Sentiment isn't a bad thing.

If your teachers suggest that your poems are sentimental, that is only half of it. Your poems probably need to be even more sentimental. Don’t be less of a flower, but could you be more of a stone at the same time?

I see a cathedral, for instance, one that’s stood for centuries and I marvel and I wonder... How many people passed through the doors? What did they pray for? How many wars did they wish to see ended? How many christenings, weddings, and funerals? Same thing with a record, I guess. Who bought it? Did they ever make love while it was playing? How many times did they read the notes in the cover? Did a song on the album change their life? I suppose it's odd to think about things like that.

Sentimentality is only sentiment that rubs you up the wrong way

Sentimentality is a superstructure covering brutality.

Sentiment is intellectualized emotion; emotion precipitated, as it were, in pretty crystals by the fancy