Like everything else, bit of common sense always helps.
Taking off 10lbs overweight from a long tarmac runway is probably not a mortal sin.
The same, on a short grass strip on a hot day, could be critical.
Just because the speed limit says 50mph, you are not gonna drive at 50 in torrential rain and heavy traffic...
The same road, no traffic, good weather, might feel extremely slow at 55..
Ivor