Every pair of lines in "Something special" sets up the same contrast. The speaker lists a flaw, such as not being smart, pretty or perfect, and then answers it with the way someone else sees her. The word "Yet" turns each confession into a small act of devotion. Where she sees a mistake, the other person sees something silly and easy to forgive. Where she sees crying, they see nothing wrong with being sensitive.
The speaker seems to carry a lot of self-doubt. She admits to saying mean things, to being a fool, and finally to hating herself. But the poem never tries to argue her out of those feelings. It simply sets them beside the steady acceptance of someone who disagrees. The ending is the most moving part: she calls herself "nothing special," yet she is told she is someone's whole world. The mood is tender and a little sad, but it finishes on warmth and relief.