who really care about others at exams?

You have to be careful - you can get thrown out if you actually help someone during the exam. If you help beforehand you run the risk of plagiarism - of using someone else's work. Or the risk of being seen to be copying. In any event., exams are often competitive - you are trying to beat everyone else - maybe only a small number of people will pass or get top grades, so helping is difficult. Also people prepare for exams differently. Maybe they cram the night before the exam and hence need absolute focus and concentration. Maybe they have to learn by rote - repeating over and over again until it sticks . I have tried preparing with and without others. If it is a very difficult exam then I need to prepare alone. For easier exams I can work with others. It all comes down to individual personality.