One reason people think Buddhists are crazy is because they teach that there is no self. One reason Buddhists think people are crazy is because they think they have a self. Buddhists go so far as to say that this idea of a separate self is the root of suffering. They are so bold as to call this sense of a separate self ignorance.
To test the Buddhist theory and see if you actually have a separate self, then try to cut yourself off. If you try to be a separate self without air, you won’t be a self for long. If you lose the Sun, you will freeze in short time. If you do without the Earth, well, again, not much self to be. You can’t be you without all the people around you. At least you need a mother, father and ancestors back to the beginning of time. So your separate self is not so separate, but it is still a self.
The self in your body is harder to refute. It is what feels all the pain. It is what gets happy and sad. It grows old. It gets sick. It gets tired. It gets hungry. It falls in love. It dances. It was born and it will die. That self has experience after experience and all those experiences strung together reinforce the idea of a self. That idea of self gets lonely, because it feels separate. Not only is that self not separate, it is not. There’s no need to feel lonely. Crazy Buddha.