Jesus didn't say your good behavior, healthy habits, or kindness to others made you well. In fact, when Jesus healed someone he was kinda like a broken record... "your faith has made you well." And apparently you don't need a whole lot of the faith stuff either! Just some to make you act on your belief - to come to, and trust Jesus with your life and wellness.
James and John did not know what it meant for the first to be last and the last to be first. But Jesus answered their request for elevated status in his kingdom by saying that they did not know what they were asking for. Jesus' kingdom is not about stars and being better than someone else.
What Jesus actually says is this ~ “Look! I stand at the door and knock. If you hear my voice and open the door, I will come in, and we will share a meal together as friends."
IN John 13.15 Jesus is saying "For I gave you an example, so that you also would do just as I did for you." And then later in the chapter he makes it even clearer... verse 34 "I am giving you a new commandment, that you love one another; just as I have loved you, that you also love one another."
Over the years, judging by our TV rhetoric - we seem to think Jesus said something quite different.