What was with all the peeing?

Would rather seen pooping. You never see people drop deuces in movies.

I enjoyed the inclusion on something so personal. Sam has a coffee cup in his hands in nearly every seen and caffeine is a diuretic therefore he’s going to pee a lot.
There are many aspects of everyday life that tv and film oftentimes exclude and I feel it does a disservice to the viewership experience, specifically, in regards to bringing the audience further into the world in which they’re partaking in.

It's not necessarily the peeing, but the fact that he was constantly drinking soda. They're probably trying to say he's in a way stuck in childhood. Maybe he used drinking soda as a kid to make himself feel better, and he's still doing it now.

Its simply to signal to the therapist guy and the audience that the bad guy is busy and out of view for whatever.

Alan realized Sam was taking forever to pee so he was counting the seconds, actually that's what I did the first time Sam was peeing lol (A League Of Their Own came to my mind) so he used that to know how much time he had while Sam was peeing so he could ...
SPOILER ALERT
.
.
.

Go and put that note inside Elias