SI..c ould be chemical thing...when we experience enjoyment or stress our bodies releases a set of chemicals, hormones or neurotrasmitters to meet the requiremnt of that stress and to combat the effects of that stress on the body......one sensation you feel during this adrenalin pumping episode is excitement and followed by numbness and relaxation... tell me if you think u can relate to this........i guess its a sort of addiction if u wish can be substituted by other sources of adrenalin.....only that it should not be self destructive.
my best wishes to all who wish to understand it and combat it..