I can't speak for anyone else, but this is my experience with Hypomania (never had any mania):
-Extreme energy: I can stay up and energized for hours and days on end
-Risk seeking behavior: I would do risky things for the thrill of it. Never things that would injure or hurt anyone else, but things that would get my adrenaline pumping: promiscuous with many partners, drinking hard and fast, diving and pushing the limits in terms of depth, looking for "trouble" at work, etc...
-Hedonistic Behaviour (Pleasure seeking): Sex with multiple partners, heavy drinking, wine drinking (love the taste!), binge eating, etc...
-Lack of sleep: I have so much energy I barely sleep
-Irritability: I never get angry or aggressive, but I get irritated easily. If I'm at work, nobody notices because I control myself. In social or personal settings I either argue with people or avoid them.
-Binge behaviour: Binge drinking, binge eating, binge sex, binge spending and buying
-Increased productivity: Not to toot my own horn, but I'm very good at my job and am very productive. When hypomanic, I get even more productive because I tend to focus on work and work feverishly without the need or desire for rest.
-I do not get aggressive or violent.
-I do not lose focus or the ability to concentrate.
-I do not have any hallucinations nor do I lose touch with reality.