I came across a scrum team where in they are typically following the below practices:
1. Adding the backlog items based on product owner wish neither estimating prior nor understanding what is the requirement
2. Adding stories anytime during the sprint time frame whenever new thing/important thing comes in
3. Not much bothered about spill overs
4. Team not sure about their capability to commit for the sprint
5. Not considering any metrics
Yet, they are comfortable with their deliverables and not willing to follow the theoretical practices