Since when is it ok NOT to work

Since when is it ok to NOT actually work while at work?
Since when is it NOT ok to tell people to GET BACK to work?

I supervise 9 staff. They all have their strengths and they all have their weaknesses....as do I. Admittedly some have more weaknesses than they do strengths but as one colleague always says "it's a rich tapestry".

My office is the second down the corridor from the main reception. Admittedly the walls are paper-thin....and I have excellent hearing....so I hear EVERYTHING that is going on within a 6 office radius.

So last week I could hear a conversation going on in reception between one of my staff members....actually the receptionist....and another staff member (whom I don't supervise). I don't recall exactly what the conversation was about but it sure wasn't about work! there was A LOT of giggling and boisterous laughter....and it continued for some time....probably at least 20 minutes.

Now I'm not the Office Grinch...no, really, I'm not! I don't mind a bit of banter between colleagues. I'm guilty of partaking myself. But when it continues for a long time, it needs to be monitored. And when the people involved are notorious for 1. not getting much done in the day and 2. having to be told at least 4 times to do a basic task....then the banter needs closer monitoring as it actually does interfere with work productivity.

So this day...after about 20 minutes of this going on....I wandered out to reception and said to them both "it doesn't sound like much work is going on out hear"....there was more giggle and some lame arse remark to which I probably then said something along the lines of "well how about we all get back to work then?" To which they did.

So imagine my surprise when my boss tells me that a staff member has called HR crying to complain that I've told her to get back to work! SERIOUSLY!!!!

There are a number of wrongs in all of this:
1. Since when is it ok for a staff member to go directly to HR rather than going to the "offending" staff member's supervisor (i.e. my boss) - my preference is that if you are offended by something someone has said or done then you actually talk one on one with them to clear the air - geez to me that is the mature adult way to deal with things!
2. Since when do these people actually think it is ok to stand around for half an hour or so actually not doing any productive work?
3. Since when is it NOT ok for a supervisor to disapprove of behaviour in the workforce and actually call people on it by saying "hey how about you get back to work"?

This is actually the second time I have had to tell these two to get back to work....somehow I don't think I'm the problem here!