1. There seems to be no way to cancel the action midway making you waste 60 energy if something goes wrong. Well, if there is, I haven't found it and would appreciate it if someone tells me how.
2. It's an exclusively competitive and solo activity due to the nature of the action. A particular firefly swarm can't accommodate two players opening their firefly jar simultaneously, usually resulting in one player getting a full jar while the other only get the leftovers if any. In addition, this coupled with problem 1 will cause the unfortunate player to waste a lot of energy for almost nothing.
3. Fireflies behavior are sometimes weird and unpredictable. They sometimes freeze in place or doesn't approach your jar for whatever reasons. I don't know if this is a problem at my end or with the game itself but it is annoying.