Why Did Arya Go Blind?

Arya went blind as an effect of wearing a face before being ready for it, before having completed her training and becoming “no-one”. Near the end of Season 5, Arya was still undergoing her training as a Faceless Man in the House of Black and White. Like most others, Arya became impatient and overconfident in her new skills and overplayed her hand. While undertaking one of her training assignments, which was to observe (only!), she spots Meryn Trant, a Lannister knight who, presumably, killed her dear first swordsmanship teacher, Syrio Forel. She disobeyed her mission and assassinated him by stabbing him repeatedly in the eyes and chest at the brothel after an ambush followed by a tough fight. 

Why Did Lord Baelish Betray Eddard Stark in Game of Thrones Season 1?

To simply answer the question, Petyr Baelish wanted one thing: power. He was born to a minor lord with nominal holdings, so he knew that he couldn’t possibly ever rule in name, but he wanted to be the real power behind the throne. For this to happen, he needed on the throne a king whom he could control. Therefore, after Robert Baratheon’s death, Baelish planned to back Joffrey’s claim to the throne and isolate him from his mother (and the Lannisters), with Ned Stark