For me- the characterizing force of hypomania is losing a sense of control over your emotions but you're able to fool yourself into thinking that you can keep up with it. So you think at a faster pace, talk fast, figure out how to more things done, have these spurts of being extremely productive, and you just can't get yourself to slow down.
One of my friends in outpatient summed it up with one word, "BAM."
When they hypomania leaves your body- it gets replaced with a sense of emptiness- complete depression. Everything that was fast- becomes slow. It's vicious.
Definitely when you're in hypo- the manic part can be very seductive- especially when it tricks you into thinking that you're just feeling really good and energetic. But for me- it's not- I hate it.