Do you think an atheist society can be successful?

I think atheistic societies have different vices. There is no such hing as a fully atheist society, just as there is no such thing as a fully Christian society. Even in a Christian 'culture', not all of those who say they believe will actually believe in their hearts. This matters because our motivations are driven by what we believe, and this determines how we act.

I'm actually currently living as a Christian in a country that has a 'secular' state, and in which atheism is encouraged through the school system. Religion is frowned upon or seen as a curio. Christianity is very rarely presened in a positive light by state schools/universities or any kind of state-subsidised cultural centre, like theatres, libraries, social and cultural programs, art galleries, museums - which are very popular centres of public life here. The people with the monopoly on 'knowledge' and 'culture' here seem to say that Christianity is something outdated and obsolete of yesteryear, and that it has done little if anything good for the world. Some people see past this, but most do not.

People still lie and cheat and backstab just like in my own nominally 'Christian' home country (in which there most people actually don't have a personal faith in Christ, but follow the moral codes left behind by those who did, once.). The difference in the secular country is that it's not seen as such as a moral scourge when it happens, and it's harder to get a complaint about such behaviour taken seriously. 'That's just life. Have you been living under a rock? Grow up.'

Attitudes are different though. People will do obviously 'altruistic' acts in public but it's not clear whether they're just doing it out of a sense of guilt - or maybe to be 'seen' doing it by others. In bigger cities sometimes pregnant women have to ask someone on the subway to give up their seat. Or, people might offer their seat to a pregnant woman but not to someone who is ill/heavy-laden/extremely tired, because the 'unwritten rule' only covers pregnant/elderly/disabled people, and so nobody would think to give them a dirty look. In bigger cities if you fall in the street sometimes nobody will help you (fear of lawsuits, 'it's none of my business', etc.). The attitude in businesses/shops/workplaces of 'I don't care about your struggle and nobody can oblige me to', or 'I'm not helping you because I won't get paid for it' or, 'It's only wrong if you get caught', is quite difficult to get used to.

But don't even get me started on the vices of so-called 'Christian' societies...

While that could be true the same thing could be applyed to any other group of people. While there would be no god or thought of do good and get into some sort of heven that would not mean moral guidelines wont develope, and with the immoral or selfish activities those depend on the person and how often those types of people would be in that society.

Nonsense. My morals have nothing to do with religious teachings, just human ones.