3 mentally unstable patients have been in a centre for over a year and the consultant want to assess their sanity level . He drew a door on the wall and asked them to open the door. Two out of three stood up and started struggling with the drawn door knob over two hours while the remaining one just sat down looking at them. The consultant thought he was getting better, so he asked him why he didn't join them, he laughed and said he's the one with the key that the other two are insane that how can they open a door without key and will open it when they are tired of struggling with the door.
The consultant just started laughing and exited the building shaking his head..
Lool.. Don't laugh alone..