Optimum number of people for half-court basketball and for conversation is similar. 2 people is tiring. 3 people is optimum. 4 is the upper limit, separation may occur. 5 is overload. You cannot play half-court with 10 people and if you are chatting it will definitely be two groups 2 + 3. So if you expect that going out with more friends means more fun, think again.