I was working at a rather large company at one time, where most of my day was spent in meetings. I had an average of 4-6 meetings a day.
Basically long stretches of boredom punctuated by moments of sheer terror.
Nowadays, I like certain types of meetings. Those done at air-conditioned restaurants where the focus is food are the best.
Day-long excursions somewhere are the worst. Usually done to sap companies of their money.
Best meeting I was ever part of followd the American standard. Done standing up, with a 20-minute time-limit. More than that, you take it offline.
Meetings that are too long are counter-productive. The hell you want to talk about, for three hours? It becomes a popularity contest, with some wannabe bitches quoting some lines from a TV show.
Any presentation with more than 12 slides is too much.
I screamed in a meeting once, and made some people cry. Not my best moment, for sure. Last I heard, they're still dead.