To an extent, You Grew On Me, for being a gorgeously written (and orchestrated, in at least one version) piece with a genuinely touching sentiment. YMMV on account of the disease metaphor.
Also to an extent, If I Didn't Have You talks about how much he loves his wife. It's just that it also talks about how much he could possibly love any number of other people instead.
His performances of "When I Grow Up" from Matilda. When so much of his show is very sarcastic and wry, here's a straightforward, peppy song from a child's perspective about how great being an adult will be.