Of course not, "any terms." But the Dilbert example you give is instructive. There are two or three possible problems: are the terms deceptive, are they unreasonable, are they under compulsion? In Dilbert's comic case, they were both deceptive (or at least hidden) and unreasonable. In many click-through licenses, there are hidden gotchas. In Microsoft's case, there was also the possible problem that the terms were forced on users because of Microsoft's market power.
In each of these cases, there are limits. We frown on deception. We frown on terms that are unreasonable, even between a willing buyer and a willing seller. (We don't let you sell yourself into slavery.) We frown on compulsion. And in fact, most contract law gives outs based on deception or compulsion, and various terms that our society have deemed unreasonable are outright illegal.
None of these situations takes away from the general case that our society values the right of people to enter into exchanges of value, and that among the things that a person "owns" are not just tangible property, but also the sweat of his or her brow, including the fruits of creative acts.