In any case, there were other lands and [Rincewind] had a facility for languages. Let him but get to Chimera or Gonim or Ecalpon and half a dozen armies couldn't bring him back. And then—wealth, comfort, security… (1.14.15)
His lack of wealth, comfort, and security is a sore point in Rincewind's existence. Ironically, all his attempts to find those things seem to push him further away from them.
"Well, if you must know, I thought he didn't mean magic. Not as such." "What else is there, then?" Rincewind began to feel really wretched. (1.15.45-47)
Another dissatisfaction of Rincewind's. The irony here is that we tend to think of magic as something that would make life way better than it is, not more complicated or wretched.
"Stands to reason," said Rerpf. "People robbing and murdering all over place, what sort of impression are visitors going to take away? You come all the way to see our fine city with its quaint customs, and you wake up dead in some back alley or as it might be floating down the Ankh, how are you going to tell all your friends what a great time you're having? Let's face it, you've got to move with the times." (1.17.71)
Twoflower's appearance in Ankh-Morpork creates an almost activist air amongst some of the citizens. They've grown dissatisfied with all the robbery and murder, and at the very least, they want the other guilds to turn it down a bit.
It is embarrassing to know that one is a god of a world that only exists because every improbability curve must have its far end; especially when one can peer into other dimensions at worlds whose Creators had more mechanical aptitude than imagination. No wonder, then, that the Disc gods spend more time in bickering than in omnicognizance. (2.Prologue.4)
Wow, even the Disc's gods are dissatisfied with their existence. What hope do all those mortal characters have at finding satisfaction with their lives?
"That's just fantasy, said Twoflower. "I know. That's the trouble." Rincewind sighed again. It was all very well going on about pure logic and how the universe was ruled by logic and the harmony of numbers, but the plain fact of the matter was that the Disc was manifestly traversing space on the back of a giant turtle and the gods had a habit of going around to atheists' houses and smashing their windows. (2.1.14-15)
As we mentioned, Rincewind has had enough of the whole magic schtick. He wants something a little more, say, scientific in his life—then things would be better for him. Oh, if he only knew….
Death, although exceptionally busy at all times, decided that He now had a hobby. There was something about the wizard that irked Him beyond measure. He didn't keep appointments, for one thing. I'LL GET YOU YET, CULLY, said Death, in the voice like the slamming of leaden coffin lids, SEE IF I DON'T. (2.13.2-3)
Even Death itself can grow dissatisfied. Now we know there is no hope for those poor mortal characters. Especially Rincewind.
If [Liessa] had a man, things would be different. Someone who, for preference, was a big strapping lad but short on brains. Someone who would do what he was told… (3.6.2)
Liessa's dissatisfaction won't be appeased until she becomes queen. In a twist on the typical fantasy damsel, she doesn't want a man to be her protector; she wants a man who'll obey orders and get her that throne.
Hrun met her gaze. He thought about his life, to date. It suddenly seemed to him to have been full of long damp nights sleeping under the stars, desperate fights with trolls, city guards, countless bandits and evil priests and, on at least three occasions, actual demigods—and for what? Well, for quite a lot of treasure, he had to admit—but where had it all gone? […] In short, life had really left him with little more than a reputation and a network of scars. (3.15.85)
Hrun has everything a man could want. In fact, the barbarian archetype from fantasy novels was designed to be everything a man could want. Think a brutish James Bond with a sword. But is Hrun satisfied? Nope.
"You were supposed to be on watch," snapped Rincewind. "I saved us from the slavers, remember," said Twoflower. "I'd rather be a slave than a corpse," replied the wizard. (4.2.6-8)
Just in case you thought there was something out there that could satisfy Rincewind. Even not becoming a slave can't lift Rincewind's perpetual dissatisfaction.
"Well, I haven't broken anything, and I haven't drowned, so what am I about to die of? You can't just be killed by Death; there has to be a reason," said Rincewind. To his utter amazement he didn't feel terrified anymore. For about the first time in his life he wasn't frightened. Pity the experience didn't look like lasting for long. (4.618.19)
Then again, Rincewind does experience a brief moment of satisfaction when he stands up to Death, erm, Scrofula. Even this comes with a hint of dissatisfaction, but we'll give him a pass since he thinks he's about to die.