Human beings suck at being wrong. We have a lot of psychological baggage preventing us from gracefully accepting defeat in an argument, probably due to the negative consequences, socially in our distant past. We have built many forms of proper debate and argument to supposedly work around this, and all of science is really built specifically to alleviate this. But even scientists can become attached, and can become petty in their defense of wrong hypothesis. This all leads to rather sad, pathetic attempts to recoup a loss. What follows are the funniest.
1: "I'm done with you/this" or "I'm going to be the bigger man and (last wordism)" etc-
This one would be fine if the argument had no clear answer, such as a topic with no evidence on either side yet, or one based purely on opinion. The problem is that it is often used to get the last word, where someone will say it a dozen times, failing to actually stop responding.
2: Ad hominems in general. They often take roundabout forms like "I make money/have a girlfriend" or "go get a life/real job/girlfriend" (financial and sexual assumptions abound).
3: My personal favorite, always make me laugh my ass off "I can do what I want/free country/freedom of speech/etc". This one is a really childish way of admitting you are wrong. If you cannot argue or leave peacefully (actually stopping is fine if it becomes annoying or stupid) but must withdraw to "I am allowed to be wrong" then you lose. End of story. I run into it constantly on Facebook and internet forums. One person keeps making points, good or bad, until the other, failing to have a counter argument says they are free to keep saying or doing or believing whatever, which was never the argument in the first place. They believe they have some freedom from critique, rather than the basic freedom to be stupid. Common in religious arguments or in anything with high emotional content, but it appears in other places. A good example from today, personally:
I criticized someone for typing an illegible comment on a friends Facebook post. They replied claiming I had no life or money or something (it really was very hard to read). I pointed out that no one speaks the way he writes and that it isn't a matter of grammar or misspelled words, but deliberate obfuscation of his writing. Communication is about passing ideas, and erecting artificial barriers (such as uncommon spellings of words, randomly dropped vowels and word substitution) was just stupid. He then responded that he is a grown up (ok odd) and was allowed to type how he wanted.
The point obviously was some minor irritant of mine, nothing of real importance, but the fact that he retreated into being "allowed" because he was a grown up to type any way he pleased didn't really mean much. He had exactly zero points in his defense, he only threw ad hominems and retreated into his right to be wrong. Fine. Be wrong, but don't expect the rest of us to be silent about it.