Reincarnation promotes the idea that people are re-born and given another chance "to get it right." As a result, the world (or society) gradually improves. However, the world’s moral decline is evidence that we are not "getting it right." Slaughter, hatred, and depravity get worse, while love, mercy, and truth are being crushed.
The other question that comes to mind is, why is it that this life—the one you’re currently living—is so crystal clear while your "past" lives are not?
The bible is plain on this subject: It is appointed for men to die once and after this comes judgment. (Heb 9:27) There is no second, third, or subsequent life, death and re-birth, but one physical death. Once you die, you will be judged, condemned for rejecting Christ, and be eternally separated from God. (John 5:24; Rev 19:20:11-14)
Those who cling to the flimsy hope of reincarnation are headed towards a hopeless and dark eternity.