I was going to write this in a jovial ranty style but I just can't, its too serious. So I'll just say it:

Do not touch your colleagues screen, ever. It's the height of rudeness. You can point without touching, it's not hard. Thanks.

I carry a pen for this exact reason

I have no depth perception so I actually can't point without touching reliably such that it's unambiguous from a very different direction, hence the pen

@lbfalvy I too use a permanent marker on my coworkers monitors.

Get a matte display and you won't care any more

depends on colleague.

If someone touches my screen, i usually don't even notice or care for that matter.

Especially when it's actually a touch screen

except there are neurological and mental diseases when people have hard time controlling their body. No, not so severe that it's visible. It's in the details, in small movements like pointing. You'll never gonna know, it's more common than you think.

I know at least one person like this very well.

(but then there are assholes who just don't care. This is a majority I believe)

@alturnativ no reason to touch a regular screen, i think it's worse, they're just leaving a fingerprint there

@kiki Can back you up here, I get muscle spasms in my limbs 24/7.

I've found that pointing to a spot on a piece of printer paper instead of the screen works just as well without being rude to colleagues.

@lbfalvy To stab the hand of the coworker that touches your screen?