I'm very interested to know about how 'the function of feelings is to enable us to experience our karma.' Does that mean that having feelings that are painful are a way to 'purify' our negative karma (not sure that's the right word - like, exhausting some bad karma we've accumulated, is what I mean)? This is a new idea to me, thank you for sending it out.
I've read that feelings like anger can be thought of as 'spontaneous arisings of mind', or 'ineffable energy'. Which would mean that in isolation they're not non-virtuous, perhaps? Pema Chodron and Dzigar Kongtrul Rinpoche have talked about 'shenpa' (Tibetan word; I'd like to hear how Rinpoche translates it (also 'zhen-pa'?)), which I believe describes that process of getting 'hooked' by a feeling you have. It's that tension, or that catch you feel right after you realize you're feeling something (I think...). In the process of getting 'hooked', that perception of that feeling energy gets turned into a dualistic 'me vs. other' storyline.
So maybe, after you have some sort of perception of some situation or other, there's the getting-hooked process, which would be, you perceive the feeling you're having, you create a story about it that involves a 'me vs something else' component, then you buy into the story, and run with it, and then you're really mad or sad, etc. That initial energy you had gets transformed into something narrow and confining.
Maybe this tendency to get hooked is an old habit of over-interpreting our feelings. It may be slightly terrifying to our egos to have a feeling but not have a storyline to go with it. If there's a feeling without ego 'owning' or seeming to give rise to that feeling, then who's really in control? Apparently ego isn't, if it didn't create that feeling. So, the getting hooked process may be ego's way of taking back control when deeper levels of mind pop out.
What I've experienced sometimes is that that anger energy can very easily turn to sadness, which turns into a sort of mirth. When I see myself get wrapped so tight inside a feeling, like a deli sandwich in butcher paper, I sometimes all the sudden forget what the storyline was, and I still have this energy that was directed to anger or sadness, but now it tickles me and makes me laugh. It's a bizarre experience, and I think it's called 'emotional lability' - diagnosable by a physician, but not a problem in Buddhism?
Best,
Katie