Us Nepalese are one of the most polite people in the world. We go out of the way to make our guests feel welcome. But the only way this system of making our guests feel welcome to our homes, our cities and our countries is if the guest reciprocates and also shows the same level of courtesy. If the guest is not of the same culture of courtesy, he could take advantage of our politeness. 

The only way the Nepali culture of politeness and courtesy with our guests can keep continuing is the guests reciprocate our positive attitude and our open hearted nature. We treat our guests like god. "Atithi Devo Bhava." But we expect our guests to also show us the level of courtesy that we show them. 

Imagine if we open our doors and invite the guest into our home. And what does the guest do in reciprocation? They decide to never leave the house. Or they decide that they will take all of our resources and not replace anything. Or let's say that they decide that they feel so at home that they don't respect the rules and regulations of that house. We expect the guest to always respect the way the house hold runs. If the guest forgets that they are only a guest and that they do not belong in that house, then it can cause many problems. If the guest feels so at home in the house that he forgets that he is only a guest, then that means that this guest has over-extended his welcome. He is taking advantage of the host to the point of being a nuisance.

At this point, the guest is a parasite, living at the expense of the host.