Could you select the best characteristic or opportunity about becoming an astronaut?

One must be a team player, work well with other people, and the perspective to see all the various factors that go into space. To live in and do things in space, you do need some unique specialties. You need something that you uniquely bring to the table, a reason for bringing you up there. You need to make your own contribution, but at the same time working as a team member

So, I would say having energy, enthusiasm and a special talent. But most importantly, being able to embody that talent within a team structure