Sarcasm is overrated anyway. Sure, it's loads of fun if done intelligently, like in the Blackadder series, to name an example. But in the hands of average people with no real particular talent for that kind of humor, you and I presumably, it often becomes this really heavy sword with which we, often unintentionally, hurt other people and thereby ourselves. I don't say that we can't make jokes on this forum (I often do), but please aim for clarity and precision in your jokes, in order to make them look like what they are, jokes, and not some kind of veiled insults. That's what I like about this forum, by the way, its crystal clarity and often brutal, childlike honesty. And it's just that sarcasm, and to a lesser extent irony, is often diametrically opposed to clear and honest thought, by obscuring and veiling it under some other thing that purports to be its opposite. Also, like other people mentioned, remember that sarcasm, in order to be properly understood, needs the support of inflections of the voice, subtle shifts in facial expression, and stuff like that. Emoticons just are too poor a substitute for that, I think.
Finally, let me remind you that the word "sarcasm" is derived from the Greek "sarkazo", i.e., to tear away the flesh. That's not a very nice thing to do, is it? Tearing away someone's flesh, I mean, even if done only metaphorically. It's really quite a brutal rhetorical device, the oral counterpart of an axe, and should only be used with great care. Just my opinion though,
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Dabey müssen wir nichts seyn, sondern alles werden wollen, und besonders nicht öffter stille stehen und ruhen, als die Nothdurfft eines müden Geistes und Körpers erfordert. - Goethe