DEPENDENCY INJECTION

What's your opinion on DI? is it just enterprise overengineering shit or it actually makes your code better and testable?

Typing is good. Languages where types aren't conceptually sets of objects, and that you can't express common set relations as constraints between types are shit e.g. Haskell. Haskell types are disjoint, and I cannot express that one type is a subset of an other. Furthermore, there is no universal type. So, Haskell a shit.