100 words isn't really that hard. A lot of times people are just lazy. Watch this, for example.
Keith walked into the room. Nobody was there, so he sat down. (12 words)
Keith walked into the room, dragging his feet a bit and sighing. Today had not been a good day. Nobody was in the room, so he sat down. (28 words)
Keith walked into the room, dragging his feet a bit and sighing. First the bad grades in potions, then being knocked over in the hall...today had not been a good day. Nobody was in the room, so he sat down. (41 Words)
Keith walked into the room, dragging his feet a bit and sighing. First the bad grades in potions, then being knocked over in the hall...today had not been a good day. And it wouldn’t have been that bad, except everyday felt like this now. He didn’t know if he was even cut out to be here. Nobody had told him it would be so hard. Glancing around, he saw that nobody was in the room, so he sat down. (80 words)
Keith walked into the room, dragging his feet a bit and sighing. First the bad grades in potions, then being knocked over in the hall...today had not been a good day. And it wouldn’t have been that bad, except everyday felt like this now. He didn’t know if he was even cut out to be here. Nobody had told him it would be so hard. Hogwarts had seemed like fun and games at first, but now he was beginning to realize there was work involved; real work. He couldn’t just skate by anymore. Glancing around, he saw that nobody was in the room, so he sat down. (108 words)
I just turned a 12 word sentence into a 108 word paragraph without much effort. Not only that, but the person can respond to my post better. They can see Keith is in a bad mood, they know why, and they can make a much better post in response to that.