Is Relief an Independent Emotion?

This may be one of those thoughts that made more sense at 2 AM last night, but I want to run with it.

The other day, I decided that "relief" was an emotion I felt very strongly. Some people get really angry, some people get really sad, some people get really happy -- I get really relieved.

And then I thought: does that make any sense? Doesn't "relief" necessarily have to piggyback on another emotion -- and that's the emotion you feel strongly or weakly?

If you're stressed about something, and that something resolves itself, you feel relief. If you feel a strong sense of relief, one might say that one has significant propensity for relief (in the same way that if you feel a strong sense of anger, you might say you have a propensity for anger). That was my initial thought -- relief hits me hard. But then I wondered whether that was a coherent thing to say, or whether the underlying stressor is what I feel strongly, and a strong sense of relief is simply the mirror image of that.

The answer must lie in whether it is possible to feel very relieved about something that is only moderately stressing you. I think that characterizes me -- I love the feeling of catharsis even without the underlying tension -- but it still doesn't quite feel like it makes sense.

Thoughts welcome.