Captain Falcon is freaking everywhere I go and I encounter ones that do the same crap over and over again. Run, dash attack or dash grab, if you grab down throw and uair, rinse and repeat. Same with Sonic! Spin Charge or Spin Dash, use an aerial attack like his bair or uair, use the Homing Attack, runaway, rinse and repeat. I also hate spammy Links that just love to use his Bow and Boomerang.
If I have to choose the most annoying character, it's a tie between Yoshi and Lucario. Yoshi is freaking powerful with his aerials, smash attacks, and Egg Throw; I'm almost afraid to go near him. With Lucario, I do fine early on, but I mess up at the end thanks to his damn aura mechanic.