To me, being successful means...
Wanting to get up and out of bed everyday. At the end of the day feeling like I did even a little thing that will last into the future.

My definition of success has changed over time. 
I used to think that I would want to retire super early or be a stay at home mom. Then I took a couple years off and found that I really need to work. I am happier with feeling like I do something productive everyday and the structure of a job helps me do that.