The problem is that some mods require some other mods to work,and then the required mods require other mods to work,and it keeps going like this...
So imagine browsing for mods...
You find a cool mod that you think is awesome and unique. You want to download it fast,and get to try it out right away. But BAM!! It requires 2 other mods to run. But the uploader didn't included links for the required mods in his mod's page,so you search for the mod on the search feature of the mod host site. And the mod host site doesn't find these mods. Then you look on Google for these mods,and you get a link,and you get to the pages where the required mods are.But you look at the descriptions of the required mods and EACH ONE REQUIRES 1-5 OTHER MODS TO BE INSTALLED PRIOR TO THEM.So you repeat the same again. And then the mods that are required for the mods that are required,for the mod you want to use,require other mods.

Ooof!
Have that happened to you too ?
How the story ended ? Did you gave up on that mod completely,or did you followed jumping from required mods to required mods,and how much time did you spend max going from required mods to required mods ?