I think it's common to be friendly or nice rather than being neutral especially regarding something you know someone has worked on. I don't think this means people are 'waiting to stab them in the back', but simply that the default state is to be friendlier.
As far as the service industry goes (which I think is different), if you're working as a waiter and you're unfriendly to the person, take forever, mess up the order, and ignore their requests (which was my friend's experience in France) then I think you're mostly not doing a good job and I think most people would think they were rude.
As far as the service industry goes (which I think is different), if you're working as a waiter and you're unfriendly to the person, take forever, mess up the order, and ignore their requests (which was my friend's experience in France) then I think you're mostly not doing a good job and I think most people would think they were rude.