Should there be an afterlife I suspect we don't all go to the same place. I would speculate that the afterlife realm will consist of different levels and/or quite distinct environments. Moreover I also suspect it wouldn't be our behaviour in and of itself which determines our final destiny in the afterlife realm, but rather what might be labelled our "intrinsic essence".
Why not our behaviour? Off the top of my head I can think of 3 reasons. Firstly, our behaviour is highly influenced by the state of our brains. Just consider someone like Phineas Gage. Or how peoples' behaviour is affected after they've consumed a large amount of alcohol. Secondly, our behavior is inevitably hugely influenced by our peers and what is deemed appropriate and acceptable and normal for ones culture. Indeed we are all actors and try to behave in a way consistent with our past actions and what other people expect of us. And thirdly, we can get into habits which are psychologically difficult to break out of.
This is not to deny there will be a correlation between behaviour in this life and our final destination. For it seems to me that our intrinsic essence will also presumably play a large role in influencing our behaviour. However, due to the aforementioned influences, this will not be a perfect correlation; indeed perhaps far from it.
So I would speculate that whether we go to a pleasant realm, or unpleasant realm, will be determined by our intrinsic essence. But what do I mean by intrinsic essence? Briefly I mean what we truly are. More specifically our capacity, or at least latent capacity, for love, empathy, compassion and so on, or contrariwise the presence of hatred, malice, self-absorption and so on.
However in my opinion it seems somewhat implausible that we will be judged by any external entities or source, rather I suspect it will be our intrinsic essence which will "gravitate" us towards the appropriate levels/environments in the afterlife realm. So finding ourselves in a pleasant environment or indeed unpleasant environment in the afterlife realm (Heaven or Hell) will not be because we are being rewarded or punished. Rather it will be our innate natures which propel us there. Of course everyone at some point will probably harbour negative thoughts, and this might temporarily propel people to those realms not entirely appropriate to their essence, but their inner essence will shortly reassert itself so that we will eventually find ourselves in that environment/level which mirrors our true essence and affinities. Of course should this be correct we will find ourselves in the company of like-minded individuals.