Comment by pdpi

> For example, you need to manage a stack to do iteration on your binary tree

Recursion around trees can get you into trouble with the stack. Consider:

    def traverse(node):
      do_work(node.payload)
      traverse(node.left)
      traverse(node.right)

The second recursive call to traverse is in tail position and is a candidate for elimination, but the first one isn't and will _always_ eat stack space. This is fine if you know what you're doing, but can bite you in the arse if you're expecting TCO to save you.