Nothing, bipolar is different for everyone.
I used to think that if that's the case, then everyone could practically be diagnosed with bipolar if they just tell they have this and this.. But what's the use if it's not stressful to you?
Anyway. If you feel like it's taking its toll on you...
You've got a genuine bipolar disorder.

Manias come in all types. My pdoc in the psych ward told me I had a "severe" mania, and I didn't think it was severe at all. I was just being sociable, a little reckless. Nothing big.

Also, manic episodes almost always end with a depressive episode. It can happen the other way round too, but usually depression comes after mania.

Some Greek psychiatrist had written about bipolar disorder that mania is the fire, and depression are the ashes that remain.

I think it was quite well said.

Sorry these thoughts are kinda scattered, like my thoughts almost always are. Hope you can make something out of it.