Thais are, in general, non-aggressive people and men are unlikely to bother you. There are a few things you should bear in mind though. Thai women are typically quite modest (except for bargirls), dress modestly, and do not touch men in public.
People will be quite friendly and helpful towards you and in general almost all areas of the city are safe for walking in, even at night. Use good common sense and stay away from deserted areas and seedy bars and clubs.