25 Quests Only

Why do they limit your quest log to 25 quests only?

Do PDAs and iPhones in WoW only have enough RAM to store 25 to-do's? What gives? I can carry hundreds of tons of ore in my backpack, but I can only carry 25 pieces of paper with some guy's mission written down on it?

I'm sure there's a reason they implemented this, so I'd be curious as to the motivation.

It becomes a big pain when leveling between Stranglethorn Vale and Dustwallow Marsh. Then I take a dip on down to Tanaris to turn in a couple Shimmering Flats quests, and I find 10 quests that are available to grab in Tanaris.

But that would require me to abandon a bunch of others.

Why?