The Burden of Proof

The burden of proof is the idea that a person or party making any particular claim has to provide sufficient evidence that their claim is true. While this sounds a good idea conceptually, just how difficult is it to provide proof for simple, everyday actions. Lately, in an effort to find out, I have been disputing claims made by my friends in an effort to establish whether or not it is reasonable to put the burden of proof on the individual making the claim.