If you travel by bus or train never put your feet up as this is considered extremely rude. Never say anything bad about the Royal Thai family or about Buddha as this can be punishable. Never spit or throw rubbish on the street as this holds high penalties if you are caught. Don't haggle for prices over images of Buddha as this is considered rude. Avoid street food vendors as there is a risk of catching stomach related or diahorrea problems. Always take electrolyte powders and tablets as it is pretty likely you will suffer from some form of diahorrea problem even if you are really careful. This is especially important regarding young children. If you visit a temple, you must cover up your arms, feet and legs. Otherwise you will be forced to change (for free) into 'borrowing' clothes where you will have to leave some form of ID, or you will not be allowed to enter the temple.