We use the world 'blasé' in English as well. Obviously it's a word we've borrowed from the French.
In English it means to be unworried or unconcerned about something, in particular something that we probably should be worried about. It doesn't mean to be 'pissed off' about something at all. So for example,
I tried to explain to her that her electricity was about to be cut off, but she was quite blasé about it.
Does blasé not have the same meaning in French then?
I've never heard it used with the 'youngspeak' meaning to which Jean-Michel refers. But I've heard it used in much the same way as in English to refer to indifference or boredom resulting from an excess of pleasure (as in the elephant story above)
In Supercaillet's original sentence, I insist that "blasé" does mean "utterly pissed off" as any English-speaking French teenager could easily confirm.
The noun related to the adjective is "la blase", in most cases used in the phrase "avoir la blase". e.g. : "J'ai la blase, mes parents veulent pas que j'aille en boite samedi soir". "J'ai la blase" means the same as "je suis super blasé".
i never use "avoir la blase" (blase is in my dictionary but doesn't mean that at all) but "être blasé" wich means: "Dont les sensations, les émotions ont perdu leur vigueur et leur fraîcheur, qui n'éprouve plus de plaisir à rien" So it means the same as the english definition Broglet gave.
The standard meaning of "blasé" in french is the same as described for the English meaning. When one has been doing something for too long he becomes bored by it, he loses his enthousiasm about this. That's the regular meaning of "blasé"
But for the 1st sentence here (Supercaillet's) "Je suis super blasé par ce qui m'est arrivé hier soir!"
The reference to "par ce qui m'est arrivé hier soir" indicates that it means "pissed off" here.
Even though this is not the real standard meaning. It's a very "slang" way of talking, and this extended meaning was probably derived from the first one