Man arrested for 2x4 labeled "High Powered Rifle"
The first ten amendments were done as a unit and were done when the drafters of the Constitution basically said "hey, we've said how the federal government works, but we haven't explicitly secured individual rights." They are considered the cornerstones of a free society in America--freedom of speech, freedom of religion, freedom of peacable assembly, freedom from unreasonable searches and seizures, freedom from cruel and unusual punishments, freedom to bear arms, etc.
The only other Constitutional Amendment that is held in that same light is the Fourteenth Amendment, enacted post-Civil-War, which made clear that states could not infringe on federally-protected rights and also established the equal protection clause (all citizens have equal protection under the law). The thirteenth amendment (which prohibited slavery) was passed at the same time, and they're often thought of as a unit.
Other constitutional amendments have important effects but the amendments themselves are not revered. This includes the sixteenth (federal government can collect income tax) and nineteenth (women's suffrage). The eighteenth amendment (prohibiting alcohol) is widely recognized as a mistake and was repeated by the 21st. Most of the remainder are just housekeeping matters and could be revised without outraging the general populace. But don't touch the Bill of Rights. Those are, in most American's eyes, the cornerstones of freedom.