How can I go from having to poop really really bad, to feel fine shortly after and after that not having to poop for a lot of hours

Stomach was on fire this morning when I arrived at work and I really had to take a brutal shit but I opted not to because all workers gather in the coffee room in the morning to go over what needs to be done for the day and the toilet is right next to this room and you know how people can be where u have to be alone when taking a shit, so I just tried to hold it and soon after the urge to poop went away completely. This is definitely not the first time this happens so I got curious to how this works?