The original title of this post was "The problem with Lean", but that sounded negative, so I went with needy instead.
From the inside of a company, lean practices are great - they are efficient, responsive, and allow a small startup to iterate and advance at breakneck speed. The combination of early launches, measurement and constant iteration allows companies to test hypotheses and react early. It's great. From the inside.
The trouble is that from the outside no one can see this process happening. From the outside (that's from the perspective of your users, investors, fans, critics and even your family) all of this process is hidden. Which leads to the most annoying question that you can ask a lean proponent - "did you ever think of adding an option to do X", and its slightly more aggressive relative, "why didn't you add the option to do Y - seems like you really missed a trick there?".
To which the answer (if you are spending enough time thinking about your product) is a resounding, but weary, "yes, actually we have thought of that, in fact it's on the backlog. Thanks for the suggestion, though - keep them coming."
This is the answer that comes out of your mouth. The answer that hopefully stays in your head is more like this: "Yes. Yes we thought of that. And we thought of the other thing. And fourteen additional things you haven't thought to mention. In fact, if you spent the next year doing nothing but thinking of all the things we've missed, you still wouldn't have a list as long as our list of all the things we have that we want to do, because we've just spent the last two years doing exactly that. And the only reason we haven't done it already is that we now have an enormous list, and only X developers. Aaaaargh."
Don't get me wrong, this is a good problem to have - engaged users with ideas are better than disengaged users and tumbleweed, so for that be thankful. But on behalf of my fellow starter-uppers, I would ask that when offering a suggestion you should assume that they have already thought of it, and it's on a card / post-it somewhere in their office. Your validation of the idea may be all that's required to get it off the wall and into the product, but please don't assume that you thought of it first - it's just statistically not that likely**.
** It does happen - just not that often. We've implemented one truly original feature that came in from a user, which probably represents somewhere between 0.1-0.5% of the features implemented.