The people. 

Working with entrepreneurs who are out to change the world is awesome.  I'm lucky to spend my days and nights with movers, shakers, dreamers and visionaries…as Steve Jobs put it, the "Crazy Ones."  I compare this with my first few jobs in valuation and investment banking, which were remunerative but stifling and draining; I truly hated to go to work each morning.  In contrast, the passion and energy founders bring is contagious, and fires me up every day.

 

It's mentally stimulating. 

At any given time, I'm typically working with 3 to 6 different startups simultaneously, which means I slice my time up into increments devoted to each startup.  Jumping from a crowd funding startup in the morning to a hardware company at lunch to a B2B SaaS business in the afternoon lets me exercise multiple mental muscles…think Crossfit for the brain.

 

It stretches limits.

Startups are by definition doing something new; thus, many of the challenges I deal with on a day-to-day basis are also new-- whether it's structuring a new business model, analyzing a new market, or exploring a new marketing approach. Solving startup challenges is often chaotic, messy, and ambiguous; but pushing the envelope, facing new challenges and blazing new business trails is a thrill, and keeps the job fresh.

 

It's innovative. 

Related to the above, working with startups means you're always on the front lines of new trends in technology-- sometimes way out in front of them.  I worked with Kickstarter back before there was an "e" in the name, and before anyone had coined the term "crowdfunding." I spent a lot of time with Autonet, a pioneer in connecting the car to the Internet, and with Appbackr, a pioneer in mobile app distribution.  The point is-- staying on the cusp of new tech trends takes a lot of energy, but it's fun to see new industries sprout and blossom, and to know you had a (small) role in making it happen.