McGrath: I quite agree with you that someone winning the lottery, but being prevented from getting the benefits owing to a heart attack. is not ironic necessarily. It is just a piss-off. But if the news that the person won the lottery was the excitement that precipitated the heart attack, then we are definitely dealing with irony. To get highly technical, in terms of the historical meaning of the word: a man falling on a banana skin is not of itself ironic. Even if he threw the banana skin away himself, it is not necessarily ironic. It would only be ironic if he threw the banana skin down in order to make somebody else fall over, but ended up falling over on it himself.
   At least, that is how the term has been defined and used for a long time. One meaning is the "using words in the opposite sense from their literal meaning": like Mark Antony saying "Brutus is an honourable man" when we know he means the opposite. But irony also refers to a course of events that have a result which is opposite to thet expected, due to the operation of fate in a twisted way. So something that should make you happy, but actually makes you so happy that it kills you, is definitely ironic. That is a somewhat similar thing to paradox, but also different. The eseence of irony, in origin and usage, is "opposite", or disguising something so that it is completely different from its real self . And as you say, not at all the same thing as something vaguely disappointing, which is a kind of usage creeping in from America.