I honestly think some people are, as Miranda said, not good at writing stuff down.
And also maybe less is more? I remember a friend of mine years ago whose then boyfriend used to write the most cringey, overblown, messages in cards to her, they were just dreadful!
From my experience:
Songs not so good toecurlingly awful
Poems (different person!) were lovely, but especially so because he was/is terribly dyslexic, and had barely read a book let alone any poetry, so it was v touching that he went to the effort of writing them :)
Cuthbert's biggest compliment so far has been to tell me that I am incredibly lovely. Which is not quite as good as a poem, or a card, or anything, but it'll do to be going along with!