Proper tail-call optimization! I know Guido doesn't like this, but proper TCO enables you to write elegant solutions to many problems, and I think that far outw

Proper tail-call optimization! I know Guido doesn't like this, but proper TCO enables you to write elegant solutions to many problems, and I think that far outweighs a marginal improvement to ease of debugging. You can still debug TCO'd code just fine; a stack trace isn't your only tool.