Which of the following is least important when considering lab safety

. Do not operate a hot plate by yourself.  Take care that hair, clothing, and hands are a safe distance from the hot plate at all times.  Use of hot plate is only allowed in the presence of the teacher.
33. Heated glassware remain very hot for a long time.  They should be set aside in a designated place to cool, and picked up with caution.  Use tongs or heat protective gloves if necessary.
34. Never look into a container that is being heated.
35. Do not place hot apparatus directly on the laboratory desk.  Always use an insulated pad.  Allow plenty of time for hot apparatus to cool before touching it.

That would be a working theory.