Eton College is probably the most famous school in the world. It's called 'the nursemaid of British statesmen' due to its propensity to churn out future prime ministers. The Conservative Party seems to regard an Old Etonian tie as the only qualification needed for appointment as a Minister of the Crown.
Eton is a Full Boarding school: attending as a Day Boy is not an option. The boys don't just attend classes together; they live together in the boarding houses too.
After classes end for the day, the boys have a mind-boggling array of extracurricular activities. The school has its own golf course and rowing lake. There are so many activities on offer that some don't finish until 10pm.
Any boy who can't find a friend in that environment isn't going to get through the admissions process.