There's a spectrum. It generally goes something like Hypomania -> Mania -> Psychosis. (Though this isn't very accurate in the general scheme of things; you can be psychotic without being manic, and mania often incorporates some degree of psychosis.)
It can be pretty hard to draw the line between a "go-getter, ambitious, type A" personality type and someone experiencing hypomania. I think a lot of people out there lead successful and fulfilling lives while commonly in a state of hypomania.
I'd been chatting about a mutual acquaintance who was behaving a bit oddly by normal standards, continually working very long and strange hours and focusing very hard on their startup. The conversation ended something like this:
"Yeah, I wouldn't be surprised to find out that $friend has hypomania or something like that."
"Oh, really? Have they been diagnosed?"
"Diagnosed? Hah! In startupland, we don't say 'diagnosed'--we say 'funded'."