I don't think they rushed it at all. I had people close to me die before. I saw red for weeks and went mentally to places that were dark. Cersei killed her best friend breh Dany wanted to murk Cersei off rip but, was held back by Tyrion who's been a terrible hand so far, and because of that Dany had to see her best friend get her head chopped off + everyone plotting against her + her dragons dying + not being the true heir to the Iron Throne + no one appreciating her saving the Kingdom and sacrificing her entire army for them. Blame Cersei. She pushed her over the edge and kept antagonizing her only to bytch up when shyt got hot
Ok, but she didn't just go kill Cersei. She intentionally committed mass genocide.