Mentioning game mods instantly reminds me of Oblivion. I never even got to playing it properly because all of my time was spent on trying to get a good mix of mods working. Ay caramba, the mod conflict checking that resulted from that was truly something unnameable. I did that manually at the time and ran quite a few tests on what works and what doesn't.
Then I noticed that there was a mod that would have automatically been able to set load orderings for most of the mods and resolved the conflicts. That was the final straw, I quit the game completely. Haven't touched it since. It's a hellish equation because the mod community is exactly what makes Oblivion a great game instead of just an okay one, but at the same time it manages to destroy my mind!