I think the ability to be rather fuzzy about feelings may be a defence mechanism provided by our body.
After having a baby a mother can talk about experiencing pain but cannot re-live it. I remember disliking having a tooth out and remember it as being unpleasant but I can't think myself into the experience so I can really remember the pain.
In the process we lose the ability to remember pleasurable feelings too, other than in the vaguest terms. Perhaps it's nature's way of letting us put things behind us. If we were stuck in the bad experiences it would stop us moving on. If we could conjour up the good experiences it might stop our motivation to achieve and give ourself another pleasurable feeling. That may also be part of the problem with mood enhancing drugs, de-motivating the user to get pleasure in less "quick fix" ways.
