[process] Signing contracts

Every now and then I get a contract which calls for a witness to my signature. What is up with that? I understand why it works that way on notarizations, but on an ordinary contract (which I have seen hundreds of in both my Day Jobbe life and writing life) it doesn’t make any sense to me.

Witnessing is a meaningful impediment to me signing, since I live alone and work by myself — I have to make a special effort to find someone to do this.