(Pasting and adapting from one of my Reddit replies, to a comment where someone decided that I must not be doing large enough projects to have reached that conclusion:)
There was this time when I redid the code side of the most recognizable comedy club chain's site while a friend cut up the graphics. We had a one month deadline. They had a big co-branded launch with a major and appropriate cable TV channel.
Their site is and was absolute garbage; the specs called for a new ticket system, contextual streaming video, photo galleries, video galleries, artist's blogs, and a pile of other crap. We hit the deadline, kind of, in that the cutup job was rough and some of the site features were hacked up very quickly (site search was a grep -i, the calendar was `cal` run through a regex to turn it into an HTML table with the numbers turned to links, etc).
And the bastards didn't pay us. It wasn't 100% what they dreamed it would be in the end, even though it was insanely much better (I know, grammar) than what they had and a huge pile of work for a month, so the directive to use as many hours as needed to hit the deadline was cancelled, after the fact. The short version is, the more the client is asking for in the beginning, the less likely is is that they'll be happy with *anything*.
Let's put it this way. You walk up to a person on the street and ask them, "what would it take to make you happy?". They might chuckle and say, "I'm pretty happy, but right now, I'd like to figure out where I parked, I've been walking around all day". They have an immediate, reasonable need and aren't leaning on you to prop up a fragile but over developed self image. Or maybe they'll say "I want a luxury yacht... no, wait, I want the *best* luxury yacht, and the fastest car, and the biggest house, and...". These are the ones to watch out for. Nothing will suit their ego. Nothing will make them happy. Even if you did somehow manage to make the best site in the world for them, a feed ego only gets hungier. They'll happily sacrifice you and their site to their ego. Telling you that it's not good enough and they don't want it any makes them feel smarter and savvier than having the thing. Perl before swine.
P.S.: To whoever leaked the URL of my previous article to Reddit, I will hunt you down and punish you.