Probably the two most important sentences...

 ...from the AD&D 1e DMG. I bet that every one of us knows at least one person who clearly forgot (or never knew of) them!

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[whY] Quote #2

“We came to existence during the collapse of your reality. Born from your fear, your lies, your sins. Now we just wait. One day - and that day is near - we will rise and devour your souls, just as the Womb - the Machine - devoured your world. Fear not, as it’s pointless to fear the inevitable.”

- Subject Eight

[whY] Quote #1

“One thousand years ago there was the Fall - a cataclysm which destroyed the world. We have been betrayed, millions have died. We were plunged into darkness, lost everything. 

Now the backwards, primitive descendants of once great live amongst the ruins of the old order, on the Shards, the only remains of our reality. We are exposed to the unspeakable evil of the Inhuman, of the Unlife, of the Demonic. 

The end is near. 

At last.” 

Koaash, Overlord of the Red Pit

[IMPORTANT repost] Even if you're not really into non-D&D clones...

Do it! I prolly won't want to play it, but I'd read it (and nick any bits that interest me)and even if nobody's interested you should still do it. Because I may and because I can. is a great reason, but I also think all these different simulacra, clones, and rules add to the DIY DNA. Even the most obscure and uplayed of DIY games will leave some sort of impact, or inspiration that spins off into another project and adds to the community's Rules gene pool.

- Lee Reynoldson

Important quote (and its aftermath)

Mages generally do not need to carry weapons other than daggers, but those of fifth level and above can use magic swords, and those of tenth level and above may use all magic weapons. However they may never carry more than one at a time, for the use of weapon requires a mental discipline alien to the philosophy of magic, and so will interfere with a mage’s concentration if he relies on them too much.

- David A. Hargrave

I like it very much and I based some of my house rules are based on it:

• Temple Assassins (one version of Mystic) are allowed to use only daggers, but from sixth level they can use any type of one handed swords. 
• Eremites (as above - Mystic) are allowed to use only blunt weapons (as ordinary Clerics), but from sixth level they can use bows (mainly in order to hunt and survive).
• Priests of the "evil" gods (such as Cockroach King or Spider-Squid god Rresh-Eiar) are allowed to use daggers instead of bashing weapons.
• I think that I'll use Hargrave's rule for magic-users of Ortix.