Jiu-Jitsu is not different from other Martial Arts when it comes to the Traditions of it.
With its origin going back to the monks in India, we can understand why Jiu-Jitsu is called Gentle Art. The monks couldn't use weapons, so they needed to develop a way to defend theirselves, using nothing but their bodies.
From that time until now, Jiu-Jitsu as we know has evolved a lot, today we have Jiu-Jitsu as a Traditional Martial Arts, but also as a Sport and a lifestyle. Even though it evolved, some of the traditions of it remained until today, and because of it Jiu-Jitsu is becoming so popular among parents. These traditions teach even adults to follow rules, to be patient, to show respect, to have a better discipline.
One of Jiu-Jitsu most famous tradition is the act of bowing. This act is a way to show respect and gratitude for everything about Jiu-Jitsu, its founders, its Instructors, even for the Teammates sharing the mats with you. So everytime a person is going into the mats they bow to the mats, showing how greatfull they are to be part of it. That is an act of Tradition, but also a great way to leave the ego out of the mats, showing you follow the rules, you accept the teaching you've been receiving.
So, remember, next time, to show respect, bow for the mats, for your instructor and teammates. Show them you really appreciate sharing the mats with them.