“According to Professor Dunbar, human relationships are layered in ever larger circles from closest to furthest. We have on average five intimate friends, 15 best friends, 50 good friends, 150 friends, 500 acquaintances and 1,500 people we recognise on sight.” – Jan 19, 2016
因此將朋友分門別類：交心的或只是交易（transactional）或表面的，並調整期望值，有了期望值，就比較不會失望了。