I got into some trouble earlier this week for a post which was deemed a bit rude

but it was unintentional so please don't misinterpret anything I write here as being less than positive.
I think the short answer is whenever we feel we have received rubbish service we should be able to post on here. I am not very good at complaining and as a customer don't feel I need to be. If I get good service I write about it, if I get back service I write about it.
However I do think you over estimate the damage that can be done. If a business has messed up all the owner has to do, and I assume we are talking about local small business owners, is to post an apology, invite everyone in for a cup of tea and then the relationship is even stronger.
It really isnt hard and I have seen a number of local businesses get a slating on here and then rebound with a great response, the we love them even more.
Don't forget, this local shop is losing sales right now because of (perceived) grumpy staff. Surely this feedback is actually doing them a favour? Of course that does assume that they react to it and communicate that they have reacted to it.
I feel this is a little bit of shoot the messenger.
If the service is poor lets not complain about the complaints, let's work together to make the service better for us all and by default our local community.
CAC