The most visible, and stunning example of bad judgement in a person professing to be a Christian, I have ever witnessed, occurred several years ago in a combination restaurant/bar in my home town.
Many of the local church groups in our community formed a church baseball league, and the elders of the COC after long deliberation decided it wasn't unscriptural, or a known work of the Devil, so with their blessings we put together a rag-tag baseball team, and fought gallantly against the Baptist, Mennonites, the Church of God, and the champion Pentecostals.
Following one of the games a baseball player decided he was in dire need of something to drink, so the place he chose to sate his thirst was a local bar, and what he chose to drink was several bottles of beer. As he was mingling with the drunks he became loud enough for me to hear his distinctive voice in the adjacent restaurant. I casually and carefully walked over to the door leading into the bar, and much to my chagrin ... it was one of the baseball players. He was celebrating a victory with a bottle of beer in his hand while wearing a dirty baseball jersey with; "CHURCH OF CHRIST" written in big capital letters on the back.
Needless to say "church baseball" is no longer a popular subject with this particular church.
More than likely all Christians at one time or another have been guilty of hypocrisy (yep! even me,) but for some reason this incident of my brother wearing his "church jersey" in a bar while getting drunk has left an indelible mark on my mind. You may know of worse indiscretions by Christians in public, but the jersey incident has to be ranked rather high on the bad judgement list.