It's an aspect of japanese society. You have to have high adademic scores, go to the best high school, go to the best college, get the best job, and work really hard. In short, be perfect. Koto is under that pressure from her mom.
Ojichan on the other hand has the aspect of work hard to deal with. Stifling work environment, shit co workers, long hours that keeps him away from his family, the pressure to overperform and so on. Lots of pressure there as well. His work life balance is absolutely horrendous.