Why do people say being miserable is part of life?

When people say this to me it really pisses me off because it's like they are saying oh well life sucks just accept it. EFFFFFF that! Im going to fight to live happy, it's like something inside of them died? I often tell people how miserable I was going to school full-time, working part-time (20-30 hours a week), being a cross country athlete and coaching as well, all the while living at home with eight people. I ended up quitting the job because school and athletics are more important to me and my job got in the way. Many people act like work is such a big priority. I pay my own bills and don't ever ask anyone for money. They act as if this is easy and they have done it all. It's like people need to learn to listen and sympathize with people. What's wrong with people? I have listened to this crap all my life and it only made me more miserable than ever. When I decided to make my own choices I finally felt free and happy. Do you hear other people say this stuff to you? And please don't say I am being weak because I am no where near that.