I think when writing something sarcastic, it should be an unwritten rule to include an emoji, use a different font. Many sarcastic comments or comments made in jest fall flat when written as text cannot convey tone or timing which is essential in spoken sarcasm.
I could say "Nice Shirt!" or Nice Shirt!" in person you would know if I like your shirt, or if I am busting your balls... In text you have no clue.
Since most people on forums do not know people personally, you can't always tell intent of a comment.
Mostly, I think that the human brain doesn't cue in on every word when reading. It filters to get the gist without bogging down on the details. Which is why you really slow down when reading something of importance. This could explain why its easy to overlook a key word which changes the meaning of the statement.
Finally, read this quickly without pausing... its very interesting.
"It deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe."
