I get what you mean.I'll be honest, I was on edge last time I was at the MK on the ferry. This attack in Vegas is really getting to me. This is the second time this year, I've missed a terrorist attack. I was there in Vegas 2 weeks ago and I missed the terrorist attack on a police officer on the Champs-Élysées by 2 days.
It's something I think about every day getting the train into London.
I'm now always super cautious on the streets, keeping an eye on speeding vehicles, people with odd luggage on the train/tube, people who are taking photos of streets and buildings in the City/Square Mile area always suspicious to me too.