Here in the UK, there has been a major campaign to try and reduce the usage of ambulances and emergency departments. Many of our ambulances literally have "this is not a taxi" written on them.
https://i.pinimg.com/originals/5c/ff/1e/5cff1eac4bef3b52f76d...
Because it's free to use, a lot of people call ambulances when they really don't need them. Women in the early stages of an uncomplicated labour. Young people with minor injuries. Elderly people who want a repeat prescription. Discouraging these people from abusing the service without putting off people who are genuinely in need of an ambulance is a complex and delicate task.
The US healthcare system is clearly an unmitigated disaster, but our single-payer utopia has a different set of problems.