For me at least, that means exactly what you mention in your other reply below. Even more than weird operators themselves, but the problem for me is that they're hard to vocalize in my mind when reading. In other words, this:

http://stackoverflow.com/questions/7746894/are-there-pronoun...

http://www.haskell.org/haskellwiki/Pronunciation

plus any more potentially introduced by any libs, or whatever else. When I see any Haskell code, I feel that I trip on those every time. And among them, especially confusion between: -> => <- -< >>= >>