archaelus

apt-get install <something>
...
Reading Package Lists... Done
Building Dependency Tree... Done
You might want to run `apt-get -f install' to correct these:
The following packages have unmet dependencies:
...

So, I installed a package with unmet dependancies (i.e. I know that the dependancies in the deb are too strict and the installed versions will surfice - etch package on sarge that depends on not particularly different libc and not a lot else). Apt now refuses to install anything because it's whining about allegedly broken dependancies. (Also, what on earth was dpkg --force-dependancies doing if not... forcing the dependancies?!?)

apt-get -f install
Would you like to remove the packages you went to a lot of trouble to install? (Y/n/NO. NO! WHY WOULD I WANT THAT)

The suggested resolution method is... unhelpful (unless you did all this by accident I suppose, or someone else did it to you).

EVIL Plan: Modify the dependancies of the deb! MUAHAHAHAHA!
dpkg-deb --extract <deb> <directory>
vim <directory/DEBIAN/control
echo “MUAHAHAHAHA I'm modifiying your dependancies HAhaHa etc.”
dpkg-deb --build <deb> <directory>
dpkg -i <deb>
echo “Sweet sweet victory is mine!”

apt-get -f install
Everything is fine.
You win.

And now a plea to package maintainers: please don't specify the exact version of common libraries (such as libssl and libc) that you have on your system as the minimum - it makes back porting unnecessarily hard.