After reading my devotional guide this morning, I got a clear picture in my mind about why we all are different. The Bible says we are all part of the same body, we all have different roles to play. 1Cor 12:21 explains that one part of the body can't do without the other irrespective of the level of importance or attractiveness of each part.
Personally, I think the reason we are all somewhat different is because God made it so. He recognized man’s deficiency and made up for it by making a help meet for Adam. After the fall of man, a gap was created between God and man and Jesus Christ, as earlier said, came to bridge that gap. If we as Christians follow the Christ wholly, our imperfection will be made perfect.