What does "insist on something" mean? Does it deliver negative meaning?
To "insist on something" does not necessarily hold any negative connotations, it is an expression meaning to continue doing something (perhaps at the displeasure of others) or to believe or speak on the importance of something. It indicates an element of strong belief or persistence on the part of the doer. In this case, the speaker has used this expression to mean, "prioritizing/continuing to do the most important thing first could lead to a meltdown." Ex: I insist on leaving at 7AM sharp tomorrow. Any later and we'll run into traffic. Ex: My boss insists on her ideas as being the best. She doesn't like to listen to others' opinions.