Warning: The following article contains spoilers for the Game of Thrones finale. If you do not want to know what happens, stop reading!
• In the final of Game of Thrones Drogon flies to the Great Hall in the Red Fortress right after Jon Snow kills Daenerys Targaryen.  • Drogon burns the Iron Throne with his Fire Breath and then flies away with Dany's body.
• Drogon does not kill Jon – why? Here are some theories.
Daenerys Tagaryen is – was – the mother of dragons. Her three reptile babies were deeply devoted to her throughout the Game of Thrones series (until one of them became an ice zombie). The fans were a little confused when Drogon decided on Sunday evening in the grand finale not to blast Jon Snow with a deadly fire breath after Jon killed Dany.
The tense scene in the Red Fortress took place after Dany celebrated her bloody "victory" at King's Landing. When she admires the Iron Throne alone in the Great Hall, Jon comes up to her and swears his allegiance. Convinced by Tyrion and Arya that Dany will become a terrible queen (see: the smoldering skeletal remains of the city), Jon kisses Dany and punches her in the chest. Rip his aunt.
When Jon drops Dany's body to the floor, Drogon's menacing form appears. He looks at Jon threateningly for a moment … before he throws the iron throne in a thick pile of molten metal. Then he flies away with Dany's body and leaves Jon incarcerated to finally make peace for the wall.
Why did not Drogon kill Jon Snow?
As Marie Claire executes, it is impossible to know exactly because dragons can not speak, but there are a few theories that are circulating on the Internet.
: Drogon is faithful to all Tagaryens.
One possible reason is that Jon Snow is actually a Targaryen – son of Rhaegar Targaryen and Lyanna Stark. Since Tagaryens has a strong attachment to dragons – Jon even rode the dragon Rhaegal during the Battle of Winterfell! – it is possible that Drogon did not want to do any of his "own" damage.
Theory 2: Drogon agreed that Dany was a fucking queen.
Drogon witnessed Dany's "Mad Queen" side first-hand – he was her chief weapon in destroying King's Landing and killing the innocent people who lived there. Although he loved her, he might have agreed with Tyrion and Arya that she should not have ruled the seven kingdoms.
That might explain why he destroys the Iron Throne, but does not harm Jon; Drogon understands why Jon had to kill Dany, but is so loyal to the Dragon's mother that he does not want anyone else sitting on her beloved chair.
Theory 3: If Jon Snow had died, he would never have caressed Ghost again.
The most logical reason of all, IMO.