They love to work hard and do intensive labor to feel like you have accomplished something hard.
It's the only thing you know. When you grow up on a farm you learn good values of how to work hard, and respect others and the environment. You also end up getting use to hard work so if you stop farming you feel lazy. Where as city people don"t grow up in the environment where you start working at about age 10(I started milking cows when I was 8) which makes it hard for them to adjust to farming.
There are a lot more reasons but it varies from person to person you could also go to this website called why I farm and watch videos about why farmers farm to learn more
