Why on Earth would Susan leave Alphabet to go to Uber? Serious question...I think she probably has more money than she needs now, why would anyone subject thems

Why on Earth would Susan leave Alphabet to go to Uber? Serious question...I think she probably has more money than she needs now, why would anyone subject themselves to what running Uber is going to be like? Staggs I can see, he's made it pretty clear he's looking for a big job -- and as a former I-banker and public company corp fin / M&A guy, he very well may have an itch to prove he can hack it in startup-land (a la Anthony Noto).