Cultural Psychologists claim that people in different cultures have different selves. In other words, culture is inherent part of different nations and religions. It is the way people live, how they interact with each other and with the rest of the world, the thing that distinguishes cultures. Therefore, it would be immoral to have a single culture in common, it would lead to crash the centuries-old cultural values and resources.

It depends on your definition of culture - culture itself is a hard to judge/define concept.

Some might argue that indigenous cultures or culture linked to an ethnic or national background change because of external influences. There is a famous study (of which I am hazy about the details) of cultural influence in Fiji that suggests that Fijian women showed significantly higher levels of eating disorders after television came to the island. The external influence of western ideals, norms and values often change culture. As does technological advancement.

Another example why cultures change is the fact that norms, values and attitudes associated with these change (can again be linked to external influences in some respects) change over time. Homosexuality used to be illegal in the UK, it was decriminalised in the 1960's and since then homosexuality has become more socially acceptable - you could also argue that divorce has become more common. Changes in the law and they way in which people go about getting a divorce made divorce easier to obtain, more people get divorced, it became less taboo.

This is merely scratching the surface

Our past decisions, thoughts and actions are what makes us who we are and those combined with our present ones would definitely contribute to who we become. Circumstances do play a major role in shaping our future.

It would be rather foolish to give ourselves completely over to destiny. Rather, we should make our own destiny. Khalil Gibran once wrote 'Bread baked without love is bitter bread that feeds but half the hunger of a man'. Similarly, work done half-heartedly will half help us achieve our goals. We need to believe in ourselves and work whole-heartedly to achieve a desired result.

We shouldn't completely give ourselves over to fate, at the same time, we need to remember that even the slightest turn of events could hinder our progress. Keeping both these points in mind, we should dedicate ourselves to what we strive to achieve, which as architects, would be our dream project.