In the campaigns we played we never ever intentionally end with cliffhangers. Ideally the party would be well rested and all set to go at the beginning of a new session.
I think that soap opers depend on the cliffhanger.
But it can easily be wrong for a group.
My regular bunch take it in turns to DM, so it can be a looong time before we continue. Therefore DMs plan to finish each session with reasonable neatness (and provide a swift summary when continuing).
Having said that, I also run the roleplaying club at my School.
Now it’s vital to finish this on time, because parents come in to collect their little darlings, who may have another commitment (music lesson etc).
So one end-of-term session was a glorious bar-room brawl. Unfortunately it took longer than I’d anticipated, mainly due to the pupils’ excellent use of every single cliche you can imagine (chandelier swinging, improvised weapons and tremendously hammy dialogue etc).
Thus when time ran out, there were still a few combat rounds to go - and the result was going to be close.
The youngsters were kept on tenterhooks right through the Summer vacation :o
(but they won!)