I would add: high-order functions like every? which accepts a predicate and a sequence and checks if the predicate is true for every item. Just imagine all the

I would add: high-order functions like every? which accepts a predicate and a sequence and checks if the predicate is true for every item. Just imagine all the for loops, null checks and what not that you save in every place where such a check is required. Same goes for sum, filter, map, reduce. Reducing accidental complexity - the core team is working hard to make things even simpler as time goes by - reducers, core.async, transducers, spec ...