'I am a very foolish fond old man' says King Lear, heartbreakingly, and although he is talking to his very dear daughter he is not speaking of his affection for her, for to Lear to be fond was to be stupid and easily deceived.
There's still a trace of this meaning in the expression fond hopes: these may be hopes for which we have an affection, but the main idea is that these hopes are unrealistic or even foolish, as in:
I have fond hopes that Millwall will win the FA Cup in my lifetime.
Nowadays the usual meaning of fond is, of course, to feel liking, love or tenderness for someone or something. Even this might have a touch of foolishness, though: a fond mother is quite likely to be blindly over-indulgent. But then, as another literary William* tells us, Love makes fools of us all, big and little, and so sadly all we can do is live in solitary bitterness or allow ourselves to be fond in both senses.
I know what I'm going to choose.
Thing To Be Today: fond. This word comes from the Middle English word fonne, a fool.