Stannis and Davos, whose last name is freaking Seaworth, were planning to confront an entire enemy navy at Blackwater. If they had sent so much as a damn fishing boat in first, they would've known the harbor was empty save for one ship leaking a mysterious neon green liquid. That screams "trap." They could have made a new plan, or sunk the boat themselves from a safe distance and sailed in unscathed. Instead, they just hoped that the enemy, who knew they were coming, hadn't bothered to prepare at all, which is generally not a sound military strategy.
Ser Barristan, Devoted Bodyguard, Abandons His Queen In The Middle Of A Civil War
Ser Barristan Selmy, the Obi Wan-esque elder in Daenerys Targaryen's ever-shrinking Queensguard, was famous for being one of the greatest swordfighters on the fictional planet. He protected her father and brother in the backstory days, and when he joins Team Dany he declares, "I was sworn to protect your family. I failed them. Allow me to join your Queensguard and I will not fail you again." Spoiler: He does.
After Dany kicks slavers out of power in Meereen and they retaliate with a plot-padding Iraq War metaphor insurrection, Dany and Barristan use a rare peaceful moment to chat about what a great singer Dany's brother was. After being told to take five and "sing a song," Barristan leaves Daenerys and heads out to what we can only assume was a Meereenese karaoke bar. He does look like a Kenny Rogers man.
Unfortunately, the Meereenese chapter of the KKK chooses this moment to ambush Dany's soldiers throughout the city, which attracts Ser Barristan and ultimately results in his death. Barristan heroically dies fighting terrorism ...