9. Mace Windu Refuses To Let Anakin Assist In The Chancellor's Arrest
Throughout much of the Clone Wars, the relationship between Mace Windu and Anakin Skywalker could be described as frosty... at best.
The true extent of Windu's lack of trust in the 'Chosen One' is on full display during the prequel-ending Revenge of the Sith. Ultimately, Windu's distrust of Anakin eventually leads to him simply going too far at a pivotal moment of the Clone Wars.
Despite bringing forward the revelation that the Chancellor was in fact the Sith Lord they'd been searching for, Windu denied Skywalker the chance to aid him in the arrest of the accused politician. In arrogantly stating that Anakin would earn his trust if his claims were true, the purple-bladed master likely nudged Skywalker even closer to the Dark Side, having already been ostracised from his peers because of the Order's restrictive rules on marriage and attachment.
Seeing Windu attempt to execute Palpatine without a trial was merely the icing on the Vader-themed cake, forcing Skywalker to give in to his feelings and cut the Jedi Master's hand off before Darth Sidious blasted him into oblivion.
Had Windu fully believed in Skywalker and brought him along to witness the Sith Lord cutting down multiple Jedi during his fight for survival, perhaps Anakin's descent into Vader territory could've been avoided.