This thought wasn't really expanded on, and it might as well be done now (Reno-boy, the post should answer one of your oldest questions). More specifically, this:

"It means not being able to promise anything, because you know that you can never guarantee something, only that you will try to make it happen. It means not being able to use definite terms such as always and never and totally and absolutely."

Let me explain.

While the experiment to attempt Complete Truthfulness may have failed, some things stayed with me. And given my fascination with language, it was but obvious it would be related to that. This meant that, for a long time, I couldn't say things like "Good morning" (I try not to). I remember driving a friend crazy over a few days over those two words. The conversations went something like this:

Day 1
Friend: "Good morning!" (was one of those early-morning cheery types)
Me: "Is it?"
Friend: "Isn't it? Why, aren't things okay with you?"
Me: "I didn't say they weren't. But you made a statement saying it was"
Friend: "It wasn't a statement. I was just wishing you!"
Me: "Ah, so you didn't mean to say 'This is a good morning', but rather 'Have a good morning'?"
Friend: "Yes!!"
Me: "Well, then, you should've said that"

Day 2Friend: "Hi. Have a good morning"Me: "Hey! Don't put pressure on me. It'll either turn out to be good morning or it won't. Don't tell me to go actively turning it into one. What's with all the stress? Why can't people just let things be? Why should I have to have a good morning - why can't it just be a nice morning, or a normal morning, or an uneventful morning? Huh? Huh?"
Friend: "Whaaaaa...?"

Day 3
Friend: "Hey...I hope you have a good morning, or any kind of morning apart from one which is not bad or harmful to you"
Me: "So it's ok if my afternoon goes bad, or my evening's a disaster? You don't love me enough to hope that my whole day goes well? What kind of a friend are you?"
Friend: "........!" *Stomachpunch*

Ok, so I deserved that (and it hurt).

But I still do it to people I've met recently, and it has changed the way I greet others. I stick to hellos, or I ask them if they're having a good morning/day. And sometimes (if it is truly a lovely day), I have no compunctions in stating "This is a wonderful morning". But I try to avoid obvious statements like that (a continued hangover of reading that bit from Hitchhiker's where Ford Prefect muses on human conversational habits*).

This habit also means that I stopped saying "Happy birthday". Because it's not. Your birth day is the day you were born. The celebration you have every year is the anniversary of your birth (day). So it should be "Happy birth day anniversary". However, given that we don't say "Happy wedding day anniversary", I've trimmed it down to "Happy birth anniversary".

And yet people react strangely every time I say that, and call it a 'typically weird (myrealname) statement'. Simply because it's not what everyone's used to hearing - regardless of whether or not it makes more sense. I can only assume it's because the former sounds better, and is less cumbersome. That, and the whole dumb-sheep thought of school.

But sooner or later, this gets very difficult. Because you begin to realise that if you have to be Truthful, you cannot make definite statements. Or rather, cannot always make such statements (see what I mean?).

Simply because you realise that when you're saying words like never or actually or always, what you really mean is (I believe it will) never/actually/always, which in itself fully means (Taking into account all that I know, it's my considered opinion that it will) never/actually/always. And since the sum total of one's knowledge is bound to be less than the actual amount of knowledge/possibilities in the world, you realise that what you're really saying is (I'm hoping that I'm right when I say that it will) never/actually/always.

I can't do that anymore.

And so my conversations, and indeed (if you've been reading this blog for long) my writing, are indefinite. Hedged. I use a lot of perhaps', and maybe's, and possibly's. There's an overpowering urge to qualify almost every statement, give an alternative option for almost every supposition or belief. And an equally overpowering urge to correct people, which in turn is only restrained by the overwhelming worry that I run the risk of turning into a pedantic bore.

Needless to say, this isn't necessarily a good thing.

But it has its perks. Especially when you get to mess with people's minds early in the morning.
* "One of the things Ford Prefect had always found hardest to understand about human beings was their habit of continually stating and repeating the obvious, as in 'It's a nice day', or 'You're very tall', or 'Oh dear you seem to have fallen down a thirty-foot well, are you alright?' At first Ford had formed a theory to account for this strange behaviour. If human beings don't keep exercising their lips, he thought, their mouths probably seize up. After a few months' consideration and observation he abandoned this theory in favour of a new one. If they don't keep on exercising their lips, he thought, their brains start working." - Douglas Adams