After losing all of her allies, Daenerys decided it was time to take matters into her own hands. Of course that meant riding in on one of her dragons. Naturally people had a lot of reactions to Dany's dragons burning people on Game of Thrones.
Thus far, Cersei has been winning the war. Euron got Ellaria, the Sand Snakes, and Yara for her. Though, really, Yara was probably more for himself. Anyway, she then surprised Tyrion by sending Jaime and the Lannister army to Highgarden instead of Casterly Rock. While the Unsullied were able to sack Casterly Rock, Euron then came by and blew up their ships. Meanwhile, Jaime took Highgarden, killed Lady Olenna, and walked away with their gold. But not before Olenna had the most epic mic drop of all time, and revealed it was she who killed Joffrey.
Regardless of the great truth bomb, she's still dead, which means Dany's totally without allies. Taking the money from Highgarden also settled Cersei's debts with the Iron Bank. In summary, she was sitting pretty.
The fact that Daenerys was somehow losing with three dragons and a ton of soldiers on her side was not lost on anyone, especially herself. That's why she was officially done with the "clever plans" and was ready to take action.
Though both Tyrion and Missandei warned against her riding in on her dragons during this war, Daenerys was officially done listening to anyone. Well, except, Jon. Still, even though he told using her dragons to burn everything and every one wasn't the best plan, Daenerys still decided to go the dragon route, just on a slightly smaller scale.
Riding in on Drogon, she, along with the Dorthraki, met up with the Lannister armies and went head to head in combat. The Lannisters didn't stand a chance though. With Drogon, Daenerys easily burned their troops to the ground, clearly a path for the Dorthraki to come through and decimate everyone.
Drogon then continued to spit out fire on pretty much any one that wasn't a Dorthraki, and though Bronn was able to hit him with a single arrow, it still wasn't enough to keep Drogon down. When Jaime attempted to take out Daenerys while she was attempting to remove the arrow from Drogon's wing, Drogon was quick to protect his mother.
Before Jaime even saw it coming, Drogon was blowing fired straight for him. Lucky for him, Bronn was there to shove him out of the way and into the nearby river. Fans will just have to wait and see if Jaime survived, though.