It's impossible to tell from a write up like this. You could have taken a little project and turned it into something big, not leveraging knowledge and resourc

It's impossible to tell from a write up like this. You could have taken a little project and turned it into something big, not leveraging knowledge and resources, and maybe misinterpreting requirements of it being 'quick and dirty'. Or - you could have a manager who lacking in perspective, which is entirely common. To boot: you could be both right, or both wrong as well. Boss could be needlessly nitpicking, at the same time as he's right about the time required. Maybe he's just in a bad mood, or under pressure, or miscommunication the requirements himself. It's also very typical of devs to nitpick their own projects and fuss around features they don't really need, corner cases etc. and forget the 'big picture' and take too long. It's a really, really hard thing to fathom. I suggest talking to your manager, letting them know that you thought you were doing well enough, that it's a surprise to you, and maybe dig in a bit on the 'actual requirements', make sure that 'timeline' is part of that. Also take a moment to make sure that you're leveraging the right tools and team knowledge, and that you're on board with the internal coding standards, and make sure to ask about communicating - its' important to you that you're doing a good job, so if something is 'off' you want to know right away from your boss. Oddly, if there are weekly updates or something along those lines ... none of this should be a surprise. Finally: Don's Sweat It. It's going to be ambiguous like this for the rest of your career, whatever you do. Try your best to put it into context, roll with it, keep your chin up, move on. If you're even asking questions like this, you're probably going to be ok.