The assumption by society at large is that a submissive sexual partner is somehow inferior or is often associated with femininity, and this can be quite damaging to the self-esteem of a bottom. There’s also stigma associated with being a bottom.
Those who identify as the top should therefore be more patient and considerate with their partner, which isn’t always the case. It should come as no surprise to anyone that anal sex can be very painful at times, and it can take a lot of getting used to before it becomes a fully satisfying sexual experience. The sex itself can also be a source of discomfort.