Being personally affected, ISIS murdering my Uncle Alan. It was surreal at the time and although me and the family were understandably distraught, I had a second wave of grief 3 years later when the Arena was bombed during the Ariana Grande concert (that woman should have a statue outside the arena by the way). It felt like the bastards had directly affected my family and my home city.
Alan had once picked me up from the Arena after an Oasis concert when me and my mates were beating up a vending machine. He never told my Dad what I was up to on the numerous occasions that he saw me whilst he was on the taxis.
I went through the weirdest period of paranoia in my life after Alan was killed. A mate from school had lived in Lyon for a time and there was a terror attack over there not long after. I sent Joe a message asking if he was alright. He was baffled until I explained about the attack in Lyon then replied "I've been living back in England for over a year Kev." There was a terror attack in Australia (Melbourne I think) and I immediately thought another mate from school had been the victim. Turns out he lived north of Sydney - a 10 hour drive from Melbourne.
I was a period of time that I truly came to understand the word "terror". Alan was killed but our family were absolutely terrorised by the whole experience.