Facebook has diluted true meaning of friends
Robin Dunbar, an anthropologist and psychologist at the University of Oxford, has long argued that humans can only really have 150 friends at a time (aka people you'd invite to a big party, not people you'd introduce to your mother.) Within that 150, there are various levels of intimacy: about 50 medium-close friends, 15 friends you can rely on for emotional support, and five intensely intimate friends - or four, if you have a romantic partner. (A romantic partner takes up the bandwidth of two close friends.)
Yet our Facebook friends number tends to be higher. Dunbar argues those "friendships" lack substance. You might like all your friends' selfies from time to time, but you don't stay in touch with them in a meaningful way. They're really acquaintances, if that. They're "friends" only in the sense that that's what Facebook connections are called. (Via Curiosity.com)
More embarrassingly simple lessons learned late in life
1. While driving a hire van on a recent school trip I asked my friend next to me which side the fuel went in. He shrugged and started hanging out the window. From the back of the van, a Year 9 kid yells: "Hey mister, just look at the triangle on the fuel gauge." After 35 years of driving, neither I nor my friend had noticed it.