Well, yeah, it's obvious that if that Sirius bloke were any sort of good wizard he'd have had the same kinds of interests as Mr Black. And then they'd have got on better.

I mean, like that bit where Mr Black talks about assisting his father with duels and all. And meanwhile his brother was being a little toerag and making his parents all berserk with filthy muggle stuff all over the place. Anybody can see that Mr Black must have had a horrible time trying to be twice as good because his brother was so bad.