Japanese people love "Omiyage" (お土産)!
But first of all, what is "Omiyage" ?
It could be translated as "souvenir" but this is not exactly that. Mainly, omiyage are local food or specialities that japanese people buy when they are traveling in another city or country like holidays, for the weekend, or for a business trip. Those kind of souvenirs are made to offer to friends, colleagues or family.
You will easily find those Omiyage boxes in stations. Boxes contain sweets, cakes, but also salty specialities separately wrapped, more convenient to offer to diffrent people.
At work, when you offer omiyage to your colleagues, you walk around the office and distribute it in person to everyone. Usually they thank you, and ask you how was it and it could start a conversation with people you usually don't have a lot of opportunity to speak with.
If some colleagues are absent, you could let your omiyage on the person's desk, so she will see it when coming back.
Bringing omiyage could also be a way to thanks people when you have been absent for few days at work.
If you have the opportunity, offer Omiyage to Japanese people, they will appreciate!