I really hate all this Trollestia/Molestia/Tyrant Celestia stuff. I don't find them funny.
Princess Celestia is not a troll.
She banished Luna to the moon because she wasn't Luna anymore. She was Nightmare Moon, she was evil, she wanted to bring eternal night. She turned Discord into stone because he was bringing chaos to ponies everywhere, and what would you expect? She couldn't have let him keep his reign of terror going on. She played a tea prank on Mr. and Mrs. Cake because she was just trying to lighten the mood and have a little fun with them. I don't see how a tiny, innocent prank makes her a troll. Yes, she didn't save Rarity when she was falling to her death, but neither did any of the other ponies or Pegasi in the crowd.
Yeah, so I REALLY don't like it when Celestia is being given the name as a troll or a tyrant.
MLP (c) Hasbro and Lauren Faust