honestly, basketball is a sport where, if you are a generally temperamental, your emotions can get the better of you very easily. 1) because basketball is a very physically and mentally taxing sport sometimes, especially in really competitive games and 2) people like this tend not to see their own faults until they've calmed down/stopped playing so they generally will try to find what everyone else is doing wrong.
Every one has bad days. The fact he apologized leads me to believe it was just that. I run with my boys and we get into arguments ALL THE TIME. But the fact of the matter is once we step outside of those lines we know that, if we went to far, we should be man enough to own that. Doesn't necessarily mean you have to accept an apology, just something to think about.
If it's just some guy you know from playing at that gym for a while and you don't know him that well, a hearty f*ck you always makes me feel better