And the young ones don't know the math behind why iterating over a list is slower than doing a lookup in a map. I don't care what new-fangled, whiz-bang languag

And the young ones don't know the math behind why iterating over a list is slower than doing a lookup in a map. I don't care what new-fangled, whiz-bang language/framework is cool. If you don't grok data structures and when to use what, you're screwed when you try to scale.