Oh, I've got one!
I hate how Kubo spent FOREVER building up how strong Ulq was, then went "oh by the way, these three are stronger" and threw them at the captains
Hmm... All of the Captain VS Espada fights also annoyed me... as the captains invariably had the perfect counter to the Espada's abilities
Here is what I mean:
Sazayel Vs Mayuri:
Sazayel- "I IS MAD SCIENTIST! I WINS BY BEING SMARTS!"
Mayuri- "I IS MAD SCIENTISTER! I ALREADY THOUGHT OF EVERYTHING YOU DO!"
Byakuya Vs Zommari
Zommari- "I is really fast!"
Byakuya- "lolol me 2!"
Zommari- "dam! Well I canz take control of 50 things!"
Byakuya- "lolol! I haz a billionz swords so I wins!"
Kenpachi Vs Nnoitra
Kenpachi- "I'm really slow, but strong and hard to cut!"
Nnoitra- "ZOMG ME TOO!"
Kenpachi- "I haz an eyepatch!"
Nnoitra- "ZOMG ME TOO!"