Even as a fresh new minnow to the site, I've experienced this. The comment'er waxing poetic about how much your post means to them/has inspired them and then leaving without an upvote, or even worse upvoting their comment and not your post.
(kicking you when you're down, when their comment makes 10X what your post does, ahahaha)

Yet for all that, there are some amazing comments that add so much value that I would refuse if possible, their upvote due to how much effort and attention they've paid me.

It's these people that restore my faith in the platform and the community, and encourage me to continue putting a consistent and sincere effort into all my comments and posts.

One example of this being @jocelynlily, Every single comment she has made on my poems has been a 270+ word explication that expands on every aspect of my post, and it's not just me but virtually every comment she makes!