Why the big suprise. unless is just syntactic sugar for if not. In the traditional manner, you should read if statements as

if condition is true do clause

so you should read unless statements as

if condition is not true do clause

(of course perl lets you write those as do ... if too)

So in your example you're saying if 1 is not true, print hello. Since 1, by definition, is true, you'll always print "WHAT?!!!\n".

-derby

update Damn ... just re-read the OP and realized the big suprise wasn't that it didn't print "Hello" but that you could place an "else" block after "unless." The syntactic sugar part still holds (its just an if (! condition)) but sorry about the rest.