It would be confusing, but this warning can be either gentle or stern depending on context and intonation. If it is used just as an advise it is usually gentle. For example you see somebody doing something prohibited and you want to warn him. If it follow some oder, it can be stern. You request from somebody to do something for you and warn him that he shouldn't fail. In the later case it is often used with "и": "И смотри, чтобы Кутузов тебя не поймал".Originally Posted by sperk