Boredom from the student themselves in classes. As well as difficulty fitting in with classmates that can't keep up with them even in conversation. Most of the times they don't even know that the other person doesn't understand what they understand so quickly. They definitely will lack social skills without exposure in other places though.

In addition, it doesn't always feel like an external pressure that they need to perform highly. Its more internalized that they want to learn the next thing and master it.

Source: I was rushed through school, but everyone's situation will be different.