Face book Friends?

I don’t comprehend the new "facebook world".... we have so many friends, however when we see them in public we do all that we can to not make eye contact! This has happened to me quite a few times in both situations...Seeing a "facebook friend" and hoping they don’t see me so I don't have to say hi and seeing a “facebook friend” and they turn to not want to say hi to me. What really rattles my brain is when "facebook friends" do it to me, I mull over it for days...did they not recognize me, am I that bad of a person they dont want to say hi, am I that annoying they don’t want to say hi? On the other hand, when I do it to others there is no worrying or late night thinking of what I did. My solution to this has been deleting one "facebook friend" a day which in truth; I would not want to say hi to them in person if we saw each other on aisle five in target. Funny thing about that...I guess some have noticed I have deleted them and they friend me again. This keeps me thinking....Do they really want to be my friend or just have a high number of friends on facebook?