Everybody we come across in our life is a gift given by god to us to experience it.
Either good or bad, there is definitely a take away from everybody. Bad qualities in others remind us how we should not be, whereas good qualities in others reminds us what we have to emulate. With all those, if we proceed our life, we can defintely improve ourselves.
But, there is no end to self-improvement and nobody is perfect in this world. Attaining perfection is what all are trying, but, nobody knows what is perfection and where it ends.