WHY IN GODS NAME ARE YOU LEAF-BLOWING AT 8AM ON A SATURDAY
These people are usually the sorts who rise at 5am regardless of day and have become bored after 3 hours awake. If they think about it at all, they believe that everyone who is not yet up by 8am is a fool who ought to be out of bed, thus that is the perfect time to make noise.
As to why they rise at 5am, take your pick from: i) Old and unable to sleep for long periods - Will be asleep again in an armchair by 11am once they've gone back inside; ii) Military bearing or wannabe - Probably has reveille.wav for an alarm; iii) Abject a-hole who gets a kick out of it. Honourable mention: iv) someone with no choice under direction from one of the above.