Misty is one of the most formidable Pokemon trainers that accompanied Ash on his journey to become a Master.
As the Cerulean Gym Leader, Misty is often seen as simply one of Ash Ketchum's companions. She is overlooked as a competent trainer in battle. Throughout the years, she has improved greatly.
From Starmie to Gyarados, Misty has some pretty powerful Pokemon at her disposal. Over the course of the anime series however, there are a few which would have been better left untrained by her.
Top 3 Pokemon Misty shouldn't have trained in the anime
#3 - Psyduck
Psyduck is definitely one of the most entertaining parts of the early anime series. Every time it appears, no one knows what will happen. It is truly a wildcard. And that is why Misty shouldn't have trained it.
It was almost untrainable in the first place. Psyduck's headaches were a constant state of uncertainty and danger. It hasn't evolved into a Golduck, and honestly, its sheer dimwittedness may be the reason it won't.
#2 - Goldeen
Goldeen was one rare instance of Misty making a battle mistake. She sent it out to fight Team Rocket on land and it usefully flopped around on the sidewalk. That seemed to be its personality in water too, however.
It could hold its own, but it often got lucky. It is yet another Pokemon that Misty did not evolve, never becoming a Seaking. Misty should have focused on powering up another Pokemon of hers or catching a different one entirely.
#1 - Togepi
Ash and his companions have an awful problem of leaving Pokemon behind, giving them away, or simply releasing them. Misty did that after her cute little Togepi evolved into an ultra capable Togetic. Every time this happens, it seems like a waste.
Yes, Misty left her Togetic to protect others of its kind, but so much more could have been done. Seeing it become a Togekiss and Misty's strongest Pokemon would have been incredible. That or not training it at all would have prevented the heartbreak.