Although it is not in my nature to 'cheat' the game, and although it might damage my player integrity, I am happy to be able to share with everyone a currently efficient way of cheating Valencia's Daily Quests. *applause*
It turns out that whatever date of quest that pops up in Valencia's Daily Quest pop-up is totally based upon the date on your computer. You may just simply opt to double-click the time display on your taskbar, and change the current date to whichever date's quest you want to do--or redo. Yes, good, bad--and chaotic--players of AQW, if you missed a day of Daily Quest, you can go back by changing your PC's date to said date that you missed.
You may also go and do quests in advance *shudders* *faints* I feel really terrible for doing this. But thankfully, AQW doesn't release the next day's daily quest until half-way through the current day on GMT+8--a conjecture, if you will.
Anyway, I found this really funny picture of kuyerjudd a few hours ago. I'd taken it about a week or so ago. It's funny. LumberJudd. lol