Maybe flip it around? The point of unhappiness (or dissatisfaction) is to get the organism to change up what it's doing; to locate new goals and pursue them. That can mean engaging with others in different ways than you did before.

If you're satisfied, you mostly stick with what you're doing already. (Which might include seeking novelty as well.) If you're unsatisfied, you may be ready to ditch your current situation for a new one as soon as one comes up.

Dementia in elders is really freakin' sad. But there's a lot of difference in people's experience of it. I happen to know two people in their 70s suffering dementia, who have very different levels of unhappiness. (They also live in rather different situations, although both are in relatively rural settings. Both live with a spouse and with supportive neighbors.)

One is largely satisfied and comfortable; the other is often pissed off and frustrated. This seems to have a lot to do with what their attitudes and social interactions were like before the dementia set in.