There is one frog, not gonna name him, that actually turned down the princess, and the princess left... over the years the frog became greener and continued kissing but, didn' find the princess again.
Sometimes appearance may fool one, sometimes not, and sometimes the frog fools himself...
Yes, I have known a few frogs like that, mates of mine in fact. Always looking for perfection, never finding it, as they don't look deeply enough or realise that it doesn't exist and so they hop around in froggy-solitude lamenting the loss of the princess they walked away from. It happens the other way too.