I think the point is: keep to yourself, and you can’t know that other people are wrong just cause they seem a certain way. Make the best of what you have control over and don’t think about the rest that you don’t have control over. Some young guy is taking up space at the front of the bus? If you can’t do anything about it then you can’t do anything about it, so don’t worry about it. Although if you CAN do something about it – then speak up and fix it.