The last time I DMed for a group of people, I had just a bit of experience from many years prior, and most of them had no experience at all. But I'd built a whole world and loose story and was excited to share it with people, so I got this group together to give it a shot.
I made the mistake of having them start out as strangers, with a grand plan to bring them together as a group. You see, I was under the misapprehension that, having agreed to play this game, they were interested in the world and story I'd set up, and would therefore take the hooks I laid for them and find reasons to work together. Because I was a fool.
When they made their characters, I asked them to fill in some basic info for me, including someone important from their life (who was still living), their greatest goal in life, and what their character's main motivation would be to go on an adventure.
Half the players tried to treat the game like a single-player sandbox video game and got frustrated and accused me of railroading them when I asked them to please not run alone into the woods in the very first scene when the characters have all just met and been given a reason to work together. At the first sign of any kind of danger, one player would simply say "my character is a coward so he would run away" and refuse to take part in anything.
One player specified in my questionnaire that his character thought himself very wise (a devoutly religious monk, in fact), but was actually very foolish, and was the type to get drawn in by get-rich-quick schemes. So I prepared a hook to draw him into the plot involving an NPC trying to sell him on a get-rich-quick scheme... which he promptly refused to engage with because he'd decided that actually his character was too zen to be tempted with worldly possessions.
When I began to get exasperated, several of the players pointed out that a good DM like Brennan Lee Mulligan never seemed to have any trouble adapting to what players wanted to do. They were unreceptive to my counter points that 1) that is his entire job, which he is paid for, and 2) his players are skilled improvisers and all actively working together to tell the best story possible.
I feel I should note that at this time, all of us in this group were in our 30s. And not, say, 14-year-olds who you might expect this entitled attitude from.
After a few sessions of desperately trying to keep the characters in the game at all without totally railroading them, I asked everyone to please watch a couple specific episodes of Adventuring Academy with Brennan Lee Mulligan which were about how to be a good player so that everyone has the best possible experience. I had already told them that I was spending literally 8 hours per week planning these sessions and trying to find ways to keep things going and keep together a group of people who desperately wanted to be brooding loners, and I promised them bonus XP at the start of the next session if they would just watch one or two of these videos.
At the start of the next session, one player proudly announced that he hadn't watched the videos, and that he wouldn't, no matter how I tried to bribe him, because he didn't think that being a player in a tabletop roleplaying game should come with homework.
When reminded (again) that I was spending 8 fucking hours a week planning these sessions, for which I was not being compensated in any way, and which he was making harder, he shrugged and said that it was my idea to start this campaign, so it was up to me to keep it going, and keep the players interested enough to keep showing up.