samseva wrote:So it would still be considered slightly offensive if someone were to sit like you mentioned (with the feet flat on the floor and the toes pointing the speaker)?
No, just ungainly. Strict Thai mothers wouldn't tolerate their children sitting like that, but if foreigners do so then their ungainliness is more likely to be tittered at than complained about.
samseva wrote:Does this also apply for when facing someone while standing? For example, if facing a monk or a Buddha image standing up, should you point your feet diagonally?
No. If you're standing up, the only way you could cause offence with your feet would be by raising one foot at least ninety degrees so that its sole was pointing at the person you intended to insult. Then to make your contempt unambiguous you would jiggle your foot back and forth. In the slum districts of Bangkok you'll sometimes see drunken Thai men doing this when they're squaring up for a fight. It's similar to English football hooligans tapping the bottom of their chins and saying, "Come on then, if you think you're hard enough!" Only it's more aggressive than that, because once somebody has pointed the soles of his feet at a Thai man, he will feel that he can't back down from a fight without serious loss of face.