Disrespectful?

Can someone explain to me the point in disrespecting another adult who has never done anything wrong to you? Or how about when a person disrespects EVERYONE else? I don't understand. What's the point? It makes no one want to respect you. Especially when I've been at work for less than an hour and you've got me in tears with all of your digs and put-downs. We're both adults. Why can't you treat me as such? I realize you are older than me by quite a few years, but that doesn't mean you're better than me, nor does it mean I'm stupid. Stop treating me like I am. And stop calling me out in front of people, especially when I've done NOTHING wrong.