It's contagious. The "Z" Zone.
The last few times I attended the weekly beading group, I brought a Zentangle tile to work on. Just needed a break from the beads for a while. I was surprised that for two weeks in a row, the person sitting next to me (2 different people) commented that they just had to look away or they would get no beading done at all. It seems that watching a person do Zentangle, possibly has the same effect as actually doing one. Mesmerizing, calming, just plain fun. If you haven't yet seen Rick and Maria's "Betweed" video, check it out, and I think you will feel what I mean by the "Z" Zone.