You are great on days that you put your heart, soul and sweat into a goal you consider magnificent. You don't need to amass a financial fortune to be great. You are great on the days you sacrifice for a greater good. You don't need to achieve your dream job to be great. You are great on the days that you're trying for your dream job, and on days that you're helping someone else improve their life.
People have a misconception about being great.
Seems that most people think they can only hope to be great someday. You are already great, it is just a matter of exercising your greatness daily. You were born great. But if you don't act great, really often, your whole body, mind and soul forgets how great you are. Greatness isn't a status that might someday be bestowed upon you- your title to forever keep.