@Jusemusepuse,
A 3 second 'hi' would have gone a long way here.
Don't be petty about this. I can see your point about the long distance stuff, but that is a separate issue. And there's every possibility that his problem with this rather small incident is nothing but other things are really what are bothering him. But he's fixating on this instead of the real issues between the two of you.
Overall, long distance relationships stink even under the best of circumstances, even when the parties communicate well. You two aren't communicating your expectations well at all when it comes to in-person visits. You expect a lot more togetherness than your boyfriend does.
Time to have a conversation about that and not the greeting incident, which is just a smokescreen over what the real problems are.