the word "I love you"

some often used this to show they care, some used this often to flirt the one they like. this is the most common sentence used by some who seeks for pleasures. but, we as humans oftentimes forget the true meaning of this. why? we tend to find happiness in temptations and so on. and we sometimes forget that we've hurt someone by getting our own personal pleasure. why is it like that? well, we're just human and we're not perfect. but, I hoped that this kind of sentence must be used properly as not to hurt another soul.