> After you sign something, it's not important if it's reasonable or not: you have to uphold it. This is simply not true. Trivial examples include a contract

> After you sign something, it's not important if it's reasonable or not: you have to uphold it. This is simply not true. Trivial examples include a contract without consideration, or an apartment lease with clauses that attempt to restrict rights granted by local law (very common in NYC). Most non-competes in the state of California are not enforceable as well, even if you agree to it.