My employer had a major national ad agency design our web site. It had a lot of problems, but these really stand out:
me (looking at design spec): So what font do you want to use for the body text? It has to be legible at very small sizes (10pixels) in order to meet the no scrolling requirement.
ad agency designer: Insignia or Geometric 415BT Medium
...
me (looking at 4 distinct frames for navigation): You do realize that 70% of the screen is being used for navigation, don't you?
designer: no. the main navigation is at the top.
me: you have frames at the top, bottom, left, and right sides for navigating leaving me content space of 380 pixels by 180 pixels. Do you want to click "Click here to continue story" twenty times just to read a press release?
...
After completing the site according to specs and launching on a Friday (after 3 weeks requesting QA) I get the following mandated changes:
1. Improve Netscape compatibility (for Netscape 4 and 6)
2. Remove Flash intro
3. allow scrolling
4. do not launch new browser window
5. add standard browser navigation
6. rewrite top navigation
7. rewrite content
All changes I advocated immediately after seeing the requirement sheet. And it only took three days of the site being live for these changes to be done after my months of complaining! But I did look good after making the requested changes in 10 hours. Of course, the sign off on those changes took another two weeks.