Hindus/caste in india
Why do people differentiate lot between caste, a higher caste people and lower caste people cannot be friends. will that cause danger if we these two caste people marry and bring bad to the society?
Caste system as PRESCRIBED by Vedas is ESSENTIAL for the well being of the society and applicable to ALL human beings in the world. But the caste system as PRACTICED in India is very bad and counter productive.
The basis of classification is three fold according to Vedas. The first and primary basis is the APTITUDE/ SKILL/ CAPABILITY of a person. The second basis is the CHOSEN PROFESSION. Every individual is free to choose his/her caste in line with these two basis. Classification based on birth is the third and default basis. Over the years, due to ignorance people classify themselves to a particular caste purely based on birth. This is WRONG and it is causing the problems that you are talking about.
The solution is to understand the true intention of Vedas in prescribing Caste system. For the well being of the society it is essential that we need people to work in different sectors like Agriculture / Industry / Technological Development/ Governance etc. Vedas suggest may a person assess his aptitude/skill/capability and chose a proper profession in which he can contribute the most. This is CASTE SYSTEM and it is GOOD.
But presently people work in different profession but still classify themselves to a totally unrelated caste (based on birth). This is BAD.
So to answer to your question why people differentiate between caste is : Ignorance.
It is not bad for the society to violate the BIRTH BASED CASTE SYSTEM.
One need to have correct understanding of the caste system as prescribed by Vedas and choose one's profession accordingly.
A same person may belong to different castes depending on the basis of classification. For example if a person born to a Brahmin becomes a minister in the Parliament then he is a Kshatriya based on his profession. Instead of working for people, if he is motivated to increase his personal wealth, he is a Vaishya by aptitude. Without using his intellect, if he merely obeys the party leader's instructions, he is a Shudra based on his capability.
Thanks for asking this important question. If you need more clarifications please do post a new question.