"Nobody can be as agreeable as an uninvited guest"

This quote by Kin Hubbard suggests that it is hard to be enjoyable when one is not welcomed. It implies that when someone is not invited to a gathering, they may not be as enjoyable as they would be if they were invited. This could be due to the fact that they feel unwelcome or out of location, and so they might not be as friendly or accommodating as they would be if they were welcomed. It could also be since they feel like they are intruding, therefore they might not be as open or interesting as they would be if they were welcomed. Eventually, this quote suggests that it is hard to be as acceptable as an unwanted visitor.