Hello,

I would like to advocate that things like `DataKinds`, `TypeFamilies`, and `GADTs` are not enabled by default in GHC2021.     The reason I ask for this is that unlike many others, I think these extensions convey useful information about the mindset you should use when working with a specific code base, which is quite different from working with ordinary Haskell.

I do think it would be quite reasonable to have an umbrella extensions for FancyTypes too, which would enable all of those, I just don't think they should be enabled for every Haskell program.

-Iavor