Don't know if this has been suggested before but here it goes.
Everyone, and I mean EVERYONE, dislikes when they see the famous message "Did not collect X Item. Try Again".
My suggestion was that for each monster that you kill and don't collect, the XP awarded for the Quest will be raised by a 10%.
In this case, if you're fighting 2 monsters and you don't collect from either of them, the awarded XP would be raised by a 20%.
It can even be a 10% for each FIGHT and not each monster.
It can be really frustrating battling over and over again the same monsters without success. This will give players motivation and some of them might even WANT not to collect just to get more XP.
It's a mighty good one! I'm on the quest Defeat Fierce Quetzal and Collect Eggs (4 of 6) and i think i've gone through about six battles with those Quetzals since it became (4 of 6). Not what i call awesome.
that's a great idea because i've had at least 5 battles with a monster in celestia i cant remember what it is though but i do kow i have to colect an ancient tablet i think so yeah it is relly frusterating.