I think another key point is that boredom is inevitable, at least at any company bigger than a startup. Software engineering is about solving problems. You get hired, and solve problems. Time passes and you get better at solving these problems, so they give you harder problems in the same domain space. Eventually you get so good at solving these problems in this domain space that you become The Guy. "Oh you have a qu…
Startups are great fun while you're building the product. Then you release it, and while you'd love to be implementing new features you're really stuck maintaining the beast you've unleashed onto the world.
In a startup there is no one else to give you a hand when things break. There is no one else to share the load of those boring tasks (deployments, unit tests, browser/phone compatibility, etc...). Even then you'll spend most of your time refining existing features, not inventing new technology.
At the end of the day, every god-awful task is on you (or a small team). While there are spikes of interesting problems, it will be a small part of what you do.