Number 3's that were good:
Gears 3
Halo 3
Sonic 3
Mario 3
Zelda 3
Fallout 3
Doom 3
Quake 3
GTA 3
Splinter Cell 3
Dead or Alive 3
Number 3's that were average, or which I'm cautious of getting excited for:
Golden Axe 3
Streets of Rage 3
Shining Force 3 PAL/US (incomplete release outside of JAP)
Ninja Gaiden 3 (starting to look formulaic, and frankly 2 was inferior to the original)
Metal Slug 3
Far Cry 3 (would love to be proved wrong)
[edit] Assassin's Creed 3
Number 3's that were bad:
Prince of Persia 3
Monkey Island 3
[edit] Age of Empires 3 was pretty damn bad.
[edit] Phantasy Star 3, which is weird because 2 and 4 were both awesome.
tl;dr: Yahtzee has a bias for short, perfectly-formed, self-contained games. Possibly this is because he's a reviewer, or possibly he's a reviewer because he plays short(er) games - but he's certainly unapologetic about not having much truck with online, multiplayer or multi-game franchises. There are a lot of people who think differently to him. To each their own.