The commas before the and were new to me. We never do that in German before an und. But knowing it now makes it easier. I don't really understand the ohter examples gramatically but I get the feeling of why mine looked bad and your example not. That is good enough for me. ;)
Thanks, I am getting the hang of this. Utopian rocks!
I am not that good at many of the underlying rules either. But I do know what is and isn't grammatical.
Here are the simple rules to using commas before "and": The only time you don't do it is when you're making a list with two items. "My friends are called Joe and Jill." If it splits a sentence into two distinct parts, you always need a comma. If you're making a list with more than two items, that's a point of contention. I support using the Oxford comma, so I say you should.