My "ah ha" moment with Haskell was when I ragequit for the 23rd time and decided that Haskell is probably not for me.
But then I came back for the 24th time and got hooked. Now Im doomed forever.
My embarrassing Haskell moment was how long it took me to realise that I could never get Arrow notation to work because the first argument to an arrow was the "arrow type" bit, so I was always trying to pass the wrong number of arguments to (*) and friends. Took me ages to get over that hump.