Whenever I have noticed enough details to believe I have a guess or a pretty darn good idea of what is going to happen, I'm almost always accurate. I often have no clue and make no attempt to guess, and in that case will run through the most likely scenarios based on what I know about people in general and the ones involved in particular, but am not attached to a particular outcome as the likely one.
When I get enough info that I have a better idea (most of it things others don't notice about facial expressions, tone of voice, choice of words, stuff like that that I couldn't really explain to another person because they're discreet and it is the complexity of how they work together that is really the key), I eliminate some of the likely outcomes and take a guess at which of the remaining ones could be the most likely. I'm still not particularly attached to one or another being more likely.
Once in a while I believe I know a person's inner workings enough, based on my knowledge of the person and the circumstances, that I can accurately predict an outcome. I've only been really wrong on those with one person to my knowledge. And that time I got it really, really wrong because what would have been reasonable assumptions to make about motives turned out to be inaccurate because of the person having a pervasive developmental disorder which provided motives I hadn't taken into consideration.
So I would say that yes, I sometimes just know how things are going to pan out and I don't believe it is anything about being psychic, just being well-attuned to particular attributes that make it easy to predict what will happen when compared to similar historical scenarios. Really, I think my personality allows me to most accurately choose a historical example to compare it to and that's why when I reach a point that I believe I have a good match, I'm almost always right.