"
I've got troubled thoughts
And the self esteem to match,
What a catch
This is putting a sardonic spin on the common term, " a catch", which means someone who would be a good romantic/etc partner. It comes from fishermen, because when they caught a good fish, they would abbreviate to just "a catch." The music video is also on a boat, to emphasize this and another lyric in the second verse. He is talking about how he is "screwed up" with his mental health, saying that nobody would actually love him because of his issues.