Do janitors find their job enjoyable and fulfilling? Probably not. Their job is still important for the functioning of society, so I wouldn't call it bullshit.
There's a real sense of accomplishment in it, and it's nice that people can immediately see and enjoy the results of your hard work. There's also something about doing manual labor that is satisfying.
And I enjoyed being "invisible" around people who used the spaces I cleaned. You usually don't exist, so people tend to continue to speak to each other as if nobody else is listening. I learned a lot about people that way.