I have one workmate which I can be weird around, but nothing otherwise.
Yesterday morning when he came in, he greeted me silently with that slight flick of your head upwards, and I did the same. Then he did the same again, and so did I. Then for about a minute or so we just kept doing that in silence before he walked off for a coffee.
On the inside I was smiling, but on the outside I had an angry face.