I suppose I would start with the basics - mood extremes. Depression is something that most people understand. Letting people know that the depression can become disabling also registers with some people. As for hypomania/mania, I would put the emphasis on extremely high energy, euphoria or extreme unwarranted anger/irritability, inability to sleep, and disinhibited and impulsive behavior. Again, to either troubling or disabling levels. If the person still didn't "get" the manic end as overly dsyfunctional, I'd start comparing it to the experience a person may have on cocaine, but without the cocaine. Psychosis and psych hospitalization is at its worst. I'd also say that bipolar disorder is a treatable brain illness, though sometimes with difficulties. Not a choice or personality trait.

What was the most pleasant thing you smelled recently?