We sorted it out and basically discovered that we were giving different meaning to yellow and red (my red is his yellow, and his red is my "fuck you we are done"). Because they are so commonly used and simple, we assumed we gave the same meaning, without realizing that we have not being frequenting the same on-line places and as such we do not share the same background ...
So one more lesson learned:
Just because it is obvious, don't think that it is obviously understood.