I think we have different things in mind.

 people´s nature is lazy. to change yourself is work, hard hard work. millions stay the same through all life. Few changes, mostly into worse as it is easier. With time people are covered with experience, coating of social status, but nature stays the same. As they say: to know person - divorce him/her first.

 life shows that we are hard to accept similarity. pure animal instinct. if we are equal, we compete in same planes and levels for the same things. we are more agressive towards those who are from the same natural habitat. we are more complaisant, tolerant and easy going with aliens. yes, we are more careful with strangers at the beginning, but are less likely "to kill" them in fight for our superiority. Thus, in certain sences union with foreigner has more chances to survive and be happy.

nevertheless, i think that happiness in relations is pure luck ). dependless on your efforts, wishes, will and other equal status

i like your position, very wise i think

 If you understand that you have bad sides and really wanna change it I think its more valid then just accept them and dont do anything to change it and harm people around you and sometimes yourself. If you get married waiting to be happy so you are running in a rong direction. Happiness depens just of ourselves ) thourgh our choices and decisions) and not of somebody else we dicide to be together forever ( or until the realtion keep working well). Some things also depends of the family where you are gonna enter.. if they accept you then take it as a bless, if they dont, be sure that they will try to convence your partner to leave you ( quite common in turkish traditions).

Lady metal I agree with most of your comments, however I do not believe it is possible to change your basic personality (or for someone to change another). 

I notice that I can be an angel in the company of some people, and a devil in the company of others!!!  I think that what we are like as people really depends on the chemistry you have with that person (bad or good), and that won´t ever change

 I am sorry if I offend you but if you behave differently according to the people you have around you so it means that you have no own personality. I didnt mean that you can change your own nature from night to day but you can try be a better person to get better results in your life instead of insisting of keep being the same moss-stone until you die.

 Of course I have my own personality.  Let me give you an example:-

Peacetrain:  Brings out the worst parts of my personality

Elisabeth: Brings out the best

 Changing according to the people that are around you has nothing to do with not having your own personality. Actually, behaving differently with different kind of people IS part of having your own personality, as long as its attached to your own personal values and ideas etc. Since no person has one straight character it is nearly impossible to behave the same all the time

 According to what I understood she said she can be a devil or an angel according to the people she has around her. The same tap cannot gives salty and drinkable water according to its interest AT SAME TÝME.

you must be devil of your boss because you dont do anything apart from posting on TC for years