Are you talking about people adjusting their clocks and their bodies to accommodate the change in time? Very few people have a big problem with that.
The problems arise when accommodating the change programmatically in code. How many times did Apple fuck this up with the first few versions of the iPhone with alarms not going off at the right time?
Never had this issue. And again, at least in Central Europe they do the change from Saturday to Sunday when it’s understood that most people have less constraints with tight times and alarms.
Considering that heart attacks rise right after the time change, and other people have sleep issues, I would guess a lot of people have a problem with adjusting their internal clicks.