The logical calculus is easier to execute than any of the techniques of mathematics itself, yet only in 1934 did Gerhard Gentzen set it out in a natural way. Even now, mathematics students are expected to learn complicated (

ε–δ)-proofs in analysis with no help in understanding the logical structure of the arguments. Examiners fully deserve the garbage that they get in return.

This quote is from Paul Taylor’s book Practical Foundations of Mathematics. Sounds like a provokative author. Unfortunately I’ll probably never read the entire book.