There's also the theory that we all have a baseline happiness that we revert to. People lose a limb and generally recover from the shock and revert to their familiar level of happiness in 6 weeks or so.

I have mostly happy memories of my Dickensian school, and can say I had a good time, even though I went through frequent periods of daily canings by the headmaster. (I don't enjoy canings!)

Maybe, Mr Roark, you are basically a happy fellow, who adjusts to his circumstances. You'll spend time relishing anyhow. You'd probably be good company in a life-raft, but a pain to be around when some proper wallowing in misery is called for.