Facebook foolishness is another way of saying "Facebook felony." Every Facebook user has or will engage in Facebook foolishness at some point, which includes but is not limited to: spying, obsessive monitoring, snooping, confusing comments, unwanted tagging, making fake profiles, unwanted messages, spamming people with requests, pokes, or likes, or getting offended by getting unfriended. The unwritten rule has become that so long as the foolishness stays within the context of Facebook or Instagram--nobody should care.