At home there are spouses and children to deal with, more phones, more computers, more time saving devices that never seem to work. Your one minute of true quiet, when you lie down in bed, is filled with thoughts of what you have to do, whose problems you have to fix, places you have to be and is gone almost immediately because you are too tired and overloaded not to shut down. Think of your grandparents' generation. Life was simpler, yes, but life was also saner. Your grandmother never had to call home from the grocery store to let everyone know she got the bread.
Life IS stressful.
Bad things happen. No one wants you to walk around happy, happy, happy all the time. People like that are imbeciles. The key is to learn what matters and what doesn't. It's here to help you stop creating stress for yourself by taking all that stuff outside you and making it internal.