What is in love, what is not?

what's not in love?
  love, care, affection,
  agony, anguish, infatuation
one thing is guarantee,
  life is different,
  than before
no matter how you close,
  the doors to ye heart,
  love tends to sneak in,
pass the tiniest hole,
  gets under your skin,
  and beguiles you
-Kazi