dont woli that much, Thai people are generally very friendly n helpful, they usually wil try their best to help when u ask them something. i met wif a few that got very good sense of humor too.

those who do business usually know some basic english... well u can safely bet that they know words like 'how much', 'cheap', 'discount', 'good', etc.

n yes, u can bargain everything in the markets there.
having say that, of coz its always good to know some basic thai, such as :
hello -> sawadikap
thank you -> krap kum kap
how much -> tao rai
* cant sure the totally correct pronunciation though.
greet n thanks the local in thai, n they'll impressed ! i once bought something from a lady, after i paid i thanked her in thai, she was like 'OMG WTF i'm impressed' n gave me another 100 baht discount.

very friendly?? I have heard many negative comments like how dangerous that place is and how you can get rob..also how the peddlers trying to cheat non locals...I really not sure and recently with the protests.. Is it still safe to go in march?? Is bangkok more dangerous than KL or JB?? If i talk to the locals or maybe the train ticket officer they can understand english?? plz advice..thanks