The plane when it’s obvious there is tons of room still where they are SITTING!

Now someone else is going to board and won’t be able to put their bag close to their seat. They will inevitably go back to where the “slow” passenger is sitting and put their bag above them. Then when we get off the plane the guy up front will often creat a bottleneck trying to get their luggage in the back. Maybe they could wait but it’s stupid they are out in that situation