What is the most realistically difficult part of orthodontic treatment?

I'm considering getting braces, but I'm curious what the most uncomfortable part is once I actually start.

Since the treatment takes a long time, I'm worried if I can endure the beginning just with willpower.

Are things like food getting stuck, brushing, and the monthly tightening pain really difficult?

I'm also worried about whether I'll need to have teeth extracted, and I'm not sure if I should also consider how my facial shape might change.

Please let me know if there are any realistic things you wish you had known before you started.