Oh really? Name one.
The Thing
Insomnia
The Girl With the Dragon Tattoo
The Departed
The Thomas Crown Affair
Of Mice and Men
True Grit
The Maltese Falcon
Scarface
The Vanishing
3:10 to Yuma
Plenty more, I'm sure, but in most cases, the original didn't get it right the first time. That's the difference. If the first was already great, then the remake is just cashing in on younger (impatient/distracted/mindless) viewers.