TL;DR should go at the front
“…brevity is the soul of wit” – Hamlet Act 2, scene 2, line 90
“Omit needless words” – Principle 17 of Strunk and White
“Civilization advances by extending the … operations which we can perform without thinking” – Alfred North Whitehead
“…do not squander time; for that is the stuff life is made of.” – Benjamin Franklin
TL;DR, which stands for Too long; didn’t read, appeared around 2002, and was originally a summary-less critique. Adding a pithy summary simultaneously preempted the criticism and made it unnecessary. Of course, the whole point of a TL;DR is lost, if you put it at the *end*! The reader has already read your longwinded essay. They don’t need the summary anymore. The greatest gift anyone can give you is their time; the greatest insult is to waste it.