There seems to be a common point of confusion in this discussion. It isn't the case that using a period implies hostility or anything else, it's using a period

There seems to be a common point of confusion in this discussion. It isn't the case that using a period implies hostility or anything else, it's using a period in a context where it's unexpected. In other words: if you avoid using periods in most messages, then use a period, it conveys just as much information about your tone as ending with an emoticon. If you always use a period, it's meaningless - but people don't, and therefore it has meaning in those situations.