It's difficult Cos they get thirsty and sand gets in their underwear ... And if they're not wearing any underwear sand gets in their everything else :O ... I've never lived in the desert though so that's just a guess .. I'm right though.
why it is difficult for people to live in the desert?
It's not always. People live in Las Vegas and Palm Springs CA, etc. Those are deserts. You just have to have a ton of money ... :)