Mania is a series of symptoms that can cause marked impairment in functioning or cause harm to self or others. I’m just brain storming here but sometimes an inflated self-esteem can reach delusional proportions, a decreased need for sleep can alter brain functions, to be more talkative than usual can screw up your social life, a subjective experience that thoughts are racing can reach psychotic proportions, distractibility and psychomotor agitation does not help, and a excessive involvement in activities with high potential for painful consequences can make a person severely dysfunctional. All of these are symptoms of mania or a person non stabilized.