Poor Etiquette

I'm sure this has been discussed but I did a brief search and didn't find a thread about it so hear I am.  

Why do people quit right before you are about to beat them?  I really don't understand why, if i'm in the process of attacking do they quit?  Just seems like poor etiquette to me.   Do they get something out of denying me the winning blow?  That's just sad.   

Now, I hate when someone has lethal and they are still playing cards instead of winning and I usually quit in that instance.  I think that is also poor etiquette because  I feel like they are wasting my time.  

What do people do in game that drive you nuts?

To save time. Or to prevent being BM'ed.

So you just answered your own question

people either don't want to sit through a bunch of animations when they know they're done for and at the same time people want to celebrate their victory by doing it in a flashy way

I concede when I know I am about to lose, dont want to waste my time and they are not entitled to my time. Only exceptions are: it was a fun match, or I want to know what silly combo I lose too.

I don’t surrender in arena after close Matches to see the last top deck of my opponent. Otherwise it depends. Some matches are just frustrating and You’re happy to leav

I totally think the opposite than OP, when lethal is obvious it's poor etiquette AND retarded to stay in game, except maybe when there's a cool animation like a Mecha'thun lethal.

Other than this, staying in game is just rudely making your opponent loose time. Just say "well played" and quit.

I find it so dumb that when I have lethal on board and my opponent is not leaving I usually counter BM by roping the lethal.

Leaving before you lose isn't poor etiquette, roping intentionally because you know you're going to lose is. When I load up a game of Hearthstone, it's not a commitment of time; I can choose to leave whenever I want to because that is how I value my time as a player. 

Playing a bunch of extra unecessary cards when you have lethal is just BM, which in moderation can be some lighthearted humour and make the win feel more gratifying. I usually play out my entire hand before I attack with my last minion, but I don't rope until the end or wait for my opponent to concede. This is just my form of BM. 

I guess I was talking about a very specific scenario.  What I was describing was this....I had to play two minions to win.  I played one and then they quit.  Why?  I genuinely don't get it.   I'm obviously playing and not screwing around playing cards needlessly.  That would be wasting time.  What do you get out of denying me the final blow?    Just quit before your last turn then or before my turn starts.  

If my turn starts and I know I can't win then I quit.  If it's my opponents turn and they have lethal on board but still play cards I quit.  Both of those are a waste of time.  If my opponent is about to win by playing their minions I just let them because they're playing and not screwing around.