9. Zam Wesell
Zam Wesell was a Clawdite bounty hunter who was tasked to assassinate Padmé Amidala by Jango Fett. However, her assassination attempt and subsequent escape were foiled by Anakin Skywalker and Obi-Wan Kenobi, mostly because of the moronic decisions Zam made.
To start, Wesell uses some poisonous bugs called Kouhuns to secretly enter Amidala's bedroom through a window in her attempt to kill the senator. Since Amidala's quarters were heavily monitored by a significant security force, including two Jedi, it's confusing why the assassin chose to attempt to infiltrate Padmé's bedroom with the bugs, rather than shooting the senator with her projectile rifle from the safety of an adjacent building. Moreover, rather than moving into a better position to shoot the senator after the bugs had been killed, Zam instead chooses to destroy the droid which Obi-Wan was holding onto and flee in her speeder.
Stranger yet, Wesell also made no use of her advantages during her escape from Anakin and Obi-Wan. Being a Clawdite, she has the ability to shapeshift into anything or anyone. So, when she runs into a bar after crashing her speeder, it is fair to assume she would shapeshift into someone else to hide in plain sight from her Jedi pursuers. However, Zam stays in the same recognisable form, and worse yet, attempts to gun down Anakin rather than discreetly escaping the bar.
With these constant stupid decisions, it's no wonder Fett would go out of his way to kill the Clawdite bounty hunter for her incompetence.