Because once you’ve been here long enough, you will watch guys like that blow out their knees, backs, shoulders etc....
some will not be able to continue their career to collect retirement.
others will retire and live with constant pain and require surgery.
That pace is not good for you in the long run. You need to look out for you. This job is a marathon not a sprint.
good work ethic is showing up on time everyday, doing a good job and making it to the finish line in good health so you can enjoy the retirement you’ve earned.