I do not like its security and not really interested in the minute by minute details of what my friends and family are doing. I hate all the silly little games that people get involved in and then try to get me to join in. I hate distant relatives sending me their resumes asking me for a job. Also dislike how some people feel free to be nasty or snide safe behind their keyboards and post comments that they would never say to your face. Also confused about how everyone on Facebook's kids are so smart. Seems that education has advanced to the point where there are no longer any not so smart kids anymore or perhaps their parents stay off of Facebook out of shame. Got to also love those "friends" who befriend you because they sell insurance, books, or whatever else they are trying to sell you. Also tend to find that Facebook lets people present themselves as they want to be viewed rather than how they really are in real life. Worst is all those little trite sayings everyone is fond of posting like, "the best gift a father can give to his children is to love their mother" or "the best thing a father can do for his children is to install morality", or "the best thing a father can do for his children is to teach them self reliance", ad nauseum. Heaven forbid someone comes up with an original line.
Last but not least, hate the way that Facebook further moves society to one where relationships are defined by an internet website and our "friends" are those who post on the web but are seldom, if ever, spoken to verbally or met in person. A society where popularity is defined by how many Facebook friends one has. It just bothers me when I hear people I know speak of friends only to find out that they mean people they have not seen in years or never at all but communicate with weekly on Facebook. Nonetheless I love Farmville. Only kidding, I quit Facebook awhile ago and my profession is in IT. I prefer my interpersonal relations to involve actually using my voice and eyes. For distant friends I email occassionally, speak on the phone with them every other month and when in their area, visit them. Surprisingly none of my close friends and family are on Facebook anymore, having once used it and found it to be lacking. YMMV