A mobile phone that increasingly has more of your life on it at that. So whereas 12 years ago you might have just lost your contact list and some fart sound boards, today you have bank apps, payment apps, tickets, cards, identification, auto logged in shopping access, and more!
I know more recent versions of android made me curse at google for adding all these guard rails and walls making doing some stuff more difficult.
On the other hand I recently had a phone fall out of my pocket and in the time it took me to get from the corner back to the place I dropped it someone had nabbed it. I was suddenly a lot more appreciative of the restrictions in place that turned my stolen device into a chargeable paper weight.