So my family and I were eating dinner tonight and the conversation ended up on manners and Ashley pointed out it was bad manners to put your elbows on the table. This example of bad manners has always bothered me, so I challenged her on it. Why? Because I couldn't think of any reason why it should be offensive, discourteous, or annoying to anyone else.
So Ashley does what she does when I challenge these things, she googled it. As she read me the results, I became even more convinced that it was a silly rule. It seemed that the most likely culprit of where this originated is noted here, and it's basically that in castles and great houses in England they didn't have large dining tables, they merely erected a temporary table that diners sat on one side of only. If you leaned on the table you could cause it to topple, which is obviously bad. So somewhere along this way this "rule" may have turned into "bad manners."
There are other explanations listed like you could be blocking others from being able to have conversation or if seated close together your elbows could cramp the space of the folks on either side of you. So sure, in those cases perhaps the act of putting your elbows on the table is indeed bad manners. But that's not because you have your elbows on the table, it's because your elbows on the table are infringing upon the will of others. The infringing on the will of others is the bad manners part, and shouldn't carry over to situations where you are NOT bothering anyone else with your elbows on the table. But these days we have enough room at our tables that this is very rarely a problem anyway!
Basically, it's an outdated part of what some folks consider "etiquette." In researching this, I found an interesting comment on a forum about this issue, and it was "etiquette is all about considering other people's sensibilities." I agree, but old rules that no longer bother anyone's sensibilities need a way to go away. Continuing them "because I said so" simply makes no sense.
Now, if you keep reading links on this subject you'll find all manner of other reasons why you shouldn't do it. Most seem contrived or completely outdated to me, and thus I'm now on a mission to destroy this tiny part of "etiquette." This rule must die.