In some ways, playing with new players is great for getting this kind of satisfying feeling. I remember once when they, at level 1, were teamed up with a much higher level fighter (only for 1 fight against a horde of kobolds, the were on their own the rest of the adventure because the story is about them, not the NPC). I remember the fighter in my group being very impressed just because the NPC was killing multiple kobolds (because she was high enough level to have multiple attacks).
In the recent game, there were a lot of good moments. All of the battles were different from anything they had faced before. I threw carrion crawlers, rust monsters, a gelatinous cube, a gibbering mouther, and a pair of warlocks against them. All of these seemed to really excite the players because of how different they were from the boring goblins/kobolds in the first couple adventures.
I remember when they fought the warlocks, one of them used a reaction spell (something Rebuke, I forget exactly) and the player controlling the dwarven fighter who hit the warlock went “Wow!”.
At another point, they met a neurotic homeless guy named Narry (who is called that because he finds a way to use the word “nary” in nearly every sentence) who told them a greatly exaggerated tale of something he saw, and I guess I did a good job doing his voice and dialogue because after I finished they were like “Dude that was awesome!”
At the end of the adventure, they came into this great hallway with sheets of fire running up the side walls, and when they killed the gargoyle there, the fire changed into water flowing the other way. That got a pretty good response from the group. Probably a cliche concept for experienced groups but these were new players so it kinda blew their minds, haha.