For me, I loved the humour in both games, but for me, the best bit, while it didn't make me laugh out loud like some bits did, was in 2 when you get to Vault city and the delightful irony of it having plenty of water, but no Geck, while 13 had an extra geck, but no water! With a hihg enough INT, your character even has the dialogue choice of "How ironic" I loved that. I love the opening video for 2 as well. Something about the littlevault guy who didn't put he goggles on always creases me!

- Try killing people in Vault City - next day there are posters with your photo hanging all around the city: " WANTED, Dead-20 000 $, Alive - 5 000 $" I just rotfl.
- After killing some people in Shady Sands go to raiders camp. They will run around screaming "The Death's Hand is back". In fact they think you are their already dead former leader :-)
- Also The Bridge of Death is hilarous - praised be Monty Python !!!
The fact is when you finish Fallout 1/2 once its not the end - its just the beginning of your experience with this marvelous game. I always encourage people to play it different ways - good, bad or even mass murderer way with different stats and perks. Its the only way to fully experience the game and its great ironic sense of humor.

right out of the dialogs:
dude: They find stuff and bring them to me and i provide for the little pai-sa-nos.
Player: You provide them pianos??
that was kinda funny hehe

a game as nihilistic as Fallout *NEEDS* a healthy dose of injection, or the game is so depressing people stop playing it

.
Yeah, that's a classic, I always choose that answer. :)
Didn't make me LOL, but it certainly made me go "What the...", standing one the side of brahmins going "moo" and one all of a sudden says "moo, I say".
Also looking at rocks and getting the message "They seem indigenous to this region".

Fallout taught me one thing: When you visit an old power plant, you don't need a flashlight to go to the toilet in the middle of a night.
And, for that matter, I also learned how to create a hole, which could be compared to Grand Canyon.
... Yes, I love Harold :D

I noticed the jump in humor from Fallout to Fallout 2, but most of it is still within the range of acceptably tongue-in-cheek. Fallout Tactics, though, is so self-referential, it's almost a letdown. Raiders mocking you about tutorials, and missing by percentage points...kinda kills the mood a bit.
Ah well. They're still good games. I can't wreck on them too badly.

the only thing that ticks me off about harold in fallout 1, is that you have to go through his dialogue a couple of different times from a different save in order to get all he has to offer.

And that's a BAD thing? :D I'd say: 'Yaaaay, more reasons to play trough game again!' :D

for a single npc's dialogue, yeah it's a bad thing.