Why overachieve in quests?

Some gathering and hunting quests are finished by delivering a Paw-Pass Ticket when certain conditions are met - say when hunting 2 of a certain monster, or delivering 10 of an item - but you can keep delivering more items or hunting more monsters.

One famous example is the HR6 quest "Coal Hearted", which ends after delivering a staggering 90 Coal, but it can also be finished by delivering a Paw-Pass Ticket that is supplied after delivering 10 Coals. A hunting example would be each of the level 6 Deviant hunts, which you can end by delivering a Paw-Pass Ticket after hunting two of the Deviant monster in question.

While I can see why sometimes you'd want to hunt a large number of monsters for various reasons, I don't know why you'd waste time on delivering more account items.

What happens when you deliver more items or hunt more monsters than you strictly need to finish the quest?