I have coined a new term, 'shooping', to describe an odd phenomenon involving human digestion and psychology. I've observed the phenomenon in myself for years, but only recently have discussed it with other people to realize it is a common experience.
Why does nature call when it does? You would think it's simple. Fluids + time will fill the bladder and create the need to urinate. Solids would do the same for 'number two'. However, I've noticed that certain situations can trigger a sudden need to poop. One of these triggers is shopping - hence the term 'shooping'.
Personally, I've noticed the strongest 'shooping' triggers when I've been in stores which have a huge variety of products. Often, I do not know exactly what I am looking for and am just 'browsing' some items I'm interested in when I get a shoop-attack. Likely places are Walgreens, Target, the library, or anyplace where I am overwhelmed by decisions on where to look. This could be different for everyone; e.g. an acquaintance of mine confirmed shoop-attacks in Ross, Old Navy, a cat store, and a halloween store (interestingly, this person loves both cats & halloween). Now you may be thinking 'hey, I've experienced shooping myself - what can I do to prevent it?'. It's very simple, a preemptive bowel movement before heading out to the store seems to stave off shoop-attacks in my experience.