Having a shitty life does not equal a get out of jail free card or a free pass to say whatever you want. It's not an excuse to be horrible to people. Shitty lives are supposed to be building blocks for something amazing. You're not supposed to let it eat you up or let it ruin the rest of your life. You're supposed to grow and come out stronger and make people say "wow". You're supposed to be an inspiration to those in the same situation as you. 

Don't succumb to the situation and become another statistic and don't use it as an excuse.