This wasn't a reason for me until reading this is even a thing. I hadn't realised someone would be listening this closely... but no thoughtcrime, so I guess to each their own. What I don't know doesn't hurt me, just don't tell me such thoughts...
My sincere apologies if this causes you additional anxiety.
I only do it for my own amusement. I don't inflict my "guessing" upon my colleagues, no one knows. For me, it's a lesson in working out "how may I maximise my anonymity".
I generally respect the "polite silence" rule upon entering the ceramic room - someone else must break the rule before I will.
Don't read on if it literally will cause more anxiety.
I was in a different 'cubicle' and noticed that the shadows meant I could see that the person next to me was using their phone, so now that's an additional consideration for minimising my identifiable footprint on the throne.