> In my experience, if you love technology and tinkering, you should absolutely not work at a startup.

This need not be essentially true. Although delivering results is of highest priority, delivering "right" results is even more important, results that create your USP, results that set you way ahead of your competitors. And that requires right amount tinkering, if you want to call it that. And that tinkering is a lot of fun - to deliver world class results in the least amount of time possible.