The emotions you experience (if you experience) may be less severe and/or more short lived, but I think they can also provide a good template for what 'normal' emotions are. Personally, I over-experience, and sometimes the intensity of the that can almost drown out the actual emotion. Do you have an internal monologue alongside any of your 'emotional' states which might point towards something real being there instead of just adrenaline? The presence of an adrenaline rush may overwhelm emotion, but it doesn't necessarily mean one isn't there. Like, for instance, if I feel anger I might think things like 'how dare he?' and get a sense of injustice over a perceived wrong. Something which causes the emotion. Or would you describe your 'rages' as more of a fight/flight response?

I think that a certain degree of 'parroting' emotion is normal. I wasn't upset at all by the movie titanic, but everyone around me was crying thus I did too. In this case, there wasn't much emotion from me regarding the event. However, during other times when I do feel something, the reactions of others can help influence how strongly those emotions take hold and my external reaction to them. This especially happens during funny movies. Laughter really can be contagious.

As for emotions 'not taking hold,' that might be a variation on normal emotional functioning? I might feel a very intense emotion that's short lived, and then come down to something more normal. Or else I might feel slightly up/down but go back to normal after rather than having it build to an extreme emotional state. If this happens very quickly for you and/or you feel you 'miss the pinnacle', then you might be going through that same process but to a lesser degree? Or I suppose it could just be parroting and hormonal reactions again.

I guess what I'm trying to figure out is whether you don't experience emotion at all, or if the emotion you do have is just extremely stunted. I can understand how a more complex reaction to emotion, such as empathy, could be lost in either case.