Okay, time to update this list
Serena: Now that I look back at it, she got on my nerves more often than any other girl. In a region-wide popularity contest, she places second to the equivalent of Lady Gaga. Sure, it was a distant second, but the pacing of the arc sucked. It made it look like she practically got that far over night. If she is so popular, then why isn't a camera constantly in her face? Aria has an entire mob that loves her so much that she has to use a disguise. Serena is apparently immune from the press. Wasted plot potential. If you want to see her character done right, I think Game!Lillie did it best.
"Everyone creates the thing they dread. Men of peace create engines of war. Invaders create Avengers. People create... smaller people? Er... children! I lost the word there. Children. Designed to supplant them. To help them end."
"Resistance. Rebellion. You will burn these ideas away."
But this is the traditional royal Canterlot voice! It is tradition to speak, using the Royal "we", and to use THIS MUCH VOLUME WHEN ADDRESSING OUR SUBJECTS!!