Mania can be the tricker of the two to recognize. Depression is a lot easier to pin point. Mania can come in different guises for different people. A lot of the problem is insight as well, when manic is can be extremely hard to even realize that you are or were. I think most people when manic loose touch with reality a bit or a lot, you're ability to think rationally or logically can be really skewed. That definitely affects our ability to always recognize it.

Hypomania is more subtle so it can be either easily recognized because you are a bit more in reality and with it. Or it can be harder to spot because of the less drastic symptoms.

You learn over time to see the patterns, signals, and symptoms of mania, but it takes time. Even after years it's something a lot of us still struggle with. Are you charting your moods? That can be a really helpful tool when it comes to this.