I got hired by a small start up a couple years back and was basically responsible for an entire platform from top to bottom. High stress? Oh you bet your ass! But god damn having full control and building out huge solutions that customers were using and giving exuberant feedback on were highs I have yet to achieve in other settings. I suffer from imposter syndrome constantly and being in that space helped reassure me I did in fact know what I was doing and was actually pretty damn good at it. The startup failed, which of course sucked, but in the end it was for the better.