Is it normal to lose facebook friends?

I am pretty quiet in person; however on facebook I have to problem statingmy opinion. I am very blunt. I have noticed that I lost a fewfriendson my friend list. Is this normal? Should I time it down? Should I not care because I am entitled to my opinion? Should I just not comment on controversial issues? I am not sure if I am being a birch or if this is normal behavior.