I have BCBS PPO as well although I think many minor things depend on your specific company's contract with BCBS.
As an example of insurance sucking...if I go in for a checkup/physical and I don't have any specific complaints, the office visit is coded as preventative and it, along with most bloodwork the doctor orders, is paid 100% with 0 copay. Every once in a while, my doctor warns me that he's ordering a specific test that might not be covered by insurance. Sometimes he's right, sometimes he's wrong...I imagine it's hard to keep up.
However, if I go in for checkup/physical and mention that my shoulder has been hurting for a little while and that I might want to get it checked out further, the office visit is coded differently and is not covered 100%. This I somewhat understand.
But all the labs that my doctor orders are also no longer covered at 100% even though my cholesterol numbers don't have much to do with a sore shoulder. That didn't seem right to me and was a surprise bill.