People are of Different Colors.

There are many types of people in this world. We all are human. No matter if we differ by skin color, hair color, race, height, weight and others, we all are having something in common, we are human. Anyway, yet we are different. According to Hinduism, your born time may affect your characteristics. Well, a scientific explaination behind this statement is that planetary movement affects the energy being received by every individuals.Thus, people does differ by the mean of their characteristics.
Some people that we meet might very extrovert. They can be social butterflies. Another person we meet might be a total introvert. You may not succeed in knowing them deeply because they might be apparently secretive. It's not the matter of which characteristic is better. For God's sake, keep in your mind, that we can never fully succeed in changing people's characteristics. If you think it is possible, you might end up in great disappointment. Unless people want to change themselves, our effort would rather be a waste.
What you can do then? Instill in them the need to change, that's all. Remember, forcing hard will not take us anywhere. So the real key of success will be patience as time will answer us.
From my personal opinion, i think the best will be finding the one who matches us well rather than someone who is not and then trying hard to change them. Furthermore, love is all about accepting people the way they are and not about changing them for our happiness. If we love each other, we should then consider changing for each other on our own initiatiave.
People are of different colors. We gotta choose the color which suits us, especially when it comes to serious relationship;) Even if we try hard to change people, will they remain same till the end? Some changes are for good, if these changes bloomed deep inside from that particular person's heart. These type of changes are far meaningful.
Relationships do fail due to poor chemistry. So follow your heart always, choose the right person. Good Luck friends!