That restaurant has been given excellent reviews by every newspaper in town. It must have an excellent staff. All generalizations are fallacious, including this one. This is a research library, so all its librarians must be involved in research. Of course I believe in Martians, since there's no evidence that they don't exist.
All trees are plants, including redwoods.
Well, this one is, because not all generalizations are fallacious. This would be a sweeping generalization , since what is at issue is not the number of examples on which it is based, but its scope. There are, certainly, plenty of examples of fallacious generalizations. But to conclude on that basis that all generalizations are fallacious ignores plenty of other examples of reasonable generalizations. An example of substituting the parts for the whole.