Which mod you thought was bad, and ended up loving it?

[kerbalfreak]

The title says it all.

For me, it's TweakScale. At first I thought "what a mess! it simply stretches everything randomly, the textures seems horrible. This will surely break my game!".

And then I tested more, and saw that are default sizes, 0.3, 0.625, 1.25, 3.75, and everything fits together. Everything was very well balanced, and most of the parts didn't have any serious problem with textures. Now I'm using it a lot! Sometimes even off the default sizes, when I need a mid-term engine/fuel tank, or the model of a high-end antenna with the specs and size of a basic one, or a very big and powerful communotron. It only messes a little with the flame animations from some engines, when scaling things up or down to much. Now I can make spacecrafts, bases and rovers much more beautiful and that looks more realistic.

Now it's a must, and something that should be in the stock game. Specially to reduce part count that you have to load in the RAM.

[ARS]

The gold standard

It adds new resource to mine: gold, with no other use other than being sold for cash. At first I'm thinking "meh, just a new resource with no use for my mission, fuel is more important". Then I ended up curiously installed it, and I realized, the further I'm going into the game, the wilder and insane my imagination become, and the bigger my craft turns out. So that mod is really helps in providing reliable source of cash during late game where anything being built can be described as sheer monstrosity (I even managed to gain over 120 million in a single trip)