A cucumber is bitter--throw it away. There are briars in the path--turn aside from them. This is enough. Do not add, "And why were such things put into the world?"

--Marcus Aurelius, Meditations, 8.50

I suggest you read the opening chapter of Consciousness Explained. Someone's posted it online here.

I think that often "logically possible" means "possible if you don't think too hard about it". Which is exactly Dennett's point in context: the idea that you are a brain in a vat is only conceivable if you don't think about the computing power that would be necessary for a convincing simulation.

Obviously the fact that it's translated complicates things, and I don't know anything about Danish. But I think the first sentence is meant to be a piece of folk wisdom akin to "Better to remain silent and be thought a fool, than to open your mouth and remove all doubt." That is, he's not really concerned with the relative proportions of regret, but with the idea that it's better (safer, shrewder) to keep your counsel than to stake out a position that might be contradicted. In light of the rest of the text, this is the reading of the line that makes the most sense to me: equivocation and bet-hedging in the name of worldly safety are a symptom of the sin of despair. Compare:

Possibility then appears to the self ever greater and greater, more and more things become possible, because nothing becomes actual. At last it is as if everything were possible--but this is precisely when the abyss has swallowed up the self.

It is said, for example, that a man ten times regrets having spoken, for the once he regrets his silence. And why? Because the fact of having spoken is an external fact, which may involve one in annoyances, since it is an actuality. But the fact of having kept silent! Yet this is the most dangerous thing of all. For by keeping silent one is relegated solely to oneself, no actuality comes to a man's aid by punishing him, by bringing down upon him the consequences of his speech. No, in this respect, to be silent is the easy way. But he who knows what the dreadful is, must for this very reason be most fearful of every fault, of every sin, which takes an inward direction and leaves no outward trace. So it is too that in the eyes of the world it is dangerous to venture. And why? Because one may lose. But not to venture is shrewd. And yet, by not venturing, it is so dreadfully easy to lose that which it would be difficult to lose in even the most venturesome venture, and in any case never so easily, so completely as if it were nothing...one's self. For if I have ventured amiss--very well, then life helps me by its punishment. But if I have not ventured at all--who then helps me?

--Soren Kierkegaard, The Sickness Unto Death

I think it does. It really is a virtuoso work of philosophy, and Dennett helpfully front-loaded it by putting his most astonishing argument in the first chapter. Anecdotally, I was always suspicious of arguments against qualia until I read what Dennett had to say on the subject. He brings in plenty of examples from philosophy, from psychological and scientific experiments, and even from literature to make things nice and concrete, and he really seems to understand the exact ways in which his position is counter-intuitive and makes sure to address the average person's intuitive objections in a fair and understanding way.

He [the Inner Game player] reasons that since by definition the commonplace is what is experienced most often, the talent to be able to appreciate it is extremely valuable.

--W. Timothy Gallwey, Inner Tennis: Playing the Game

From the remarkable opening chapter of Consciousness Explained:

One should be leery of these possibilities in principle. It is also possible in principle to build a stainless-steel ladder to the moon, and to write out, in alphabetical order, all intelligible English conversations consisting of less than a thousand words. But neither of these are remotely possible in fact and sometimes an impossibility in fact is theoretically more interesting than a possibility in principle, as we shall see.

--Daniel Dennett

To recognize that some of the things our culture believes are not true imposes on us the duty of finding out which are true and which are not.

--Allan Bloom, Giants and Dwarfs, "Western Civ"