White (any country just white) - Absolute gods in Thailand. Immigration staff will speak to you in a soft voice with smiles all around. You will be surrounded by 5 members of staff trying to help you. People will bend over backwards to help you. Schools accept you and you will bypass all those silly health checks and police checks.
Black - Treated well. Generally well treated and very popular with the ladies.
Chinese, korean, Japanese - Welcomed. You will get an acceptable level of treatment. Nothing special.
Indians, Arabs, Pakistanis - Absolute disgraceful treatment by Thai's. You will be followed around the mall. Random checks at the airports. That elevator door will be closing in your face every time. Awkward job interviews about that focus on your facial hair. Parents will pull their kids away from you.