Piccolo's Amazing Ideas:
* Goes giant when fighting Goku, allowing Goku to go inside him and rescue Kami.
* Doesn't realize that Raditz can just dodge the Special Beam Cannon, it was Goku who had the idea of grabbing him.
* Tells Raditz about the Dragon Balls, which is what made Nappa/Vegeta come to Earth.
* Uses Gohan as a weapon against Nappa, which just ends up getting Piccolo killed.
* Goes to fight Freeza, thus putting the DBs in danger, which was the whole point of going to Namek.
* Allows Freeza to transform.
* Think he can beat 3rd Form Freeza through running away, which is counter productive as it leaves Gohan an open target
* Informs Cell that he can regenerate, making Cell realize that he can regenerate too.
* Battles 17, which gives away the Androids location to Cell.
Also in the Buu arc Super Buu absorbs Piccolo for his intelligence and notice how Buu gets DUMBER. I swear its an inside joke for Toriyama.