Wawa's coffee

I usually purchase a breakfast sandwich on the way into work/school for 2.11 plus tax and use that as my breakfast fortified with whatever I can find in work.  But lately Wawa’s been running a promotion where any breakfast sandwich and any sized coffee is 1.99, cheaper than the sandwich alone so I’ve taken to getting coffee.

Recently though, the coffee has given me terrible diarrhea and the following’s resulted:
Coworker: Every morning at about 8:00 Am you seem to go.
Me: Yeah.
Coworker: Do you have a high fiber breakfast or something?
Me: No, I’ve been getting free Wawa coffee, in fact better than free but Wawa coffee gives me terrible diarrhea.
Coworker: So why don’t you stop drinking it?
Me: Then I’d feel I wasted it.
Coworker: So why don’t you stop getting it then?
Me: But, it’s free.