Although it should be readily apparent, one of the pitfalls of failing to reduce your agreement - or even a modification to an existing agreement - to writing, is that those updated provisions may not be enforceable under New York law. Seeking to collect on such "promises" proves even more difficult when the underlying agreement is clearly written, or in legalese, "unambiguous."

In those cases, New York's courts have held as follows:

"[C]ourts may not by construction add or excise terms, nor distort the meaning of those used and thereby make a new contract for the parties under the guise of interpreting the writing.'" Vt. Teddy Bear Co. v. 538 Madison Realty Co., 1 N.Y.3d 470, 475 (App. Div. 2004); see also, Law Debenture Trust Co. of N.Y. v. Maverick Tube Corp., 595 F.3d 458, 467 (2d Cir. 2010) ("[T]he court should not find the contract ambiguous where the interpretation urged by one party would 'strain[] the contract language beyond its reasonable and ordinary meaning." (quoting Bethlehem Steel Co. v. Turner Constr. Co., 141 N.E.2d 590, 593 (N.Y. 1957))."

And, once the contract is deemed unambiguous, the law - at least insofar as New York is concerned - is equally clear: "Where the agreement is unambiguous, a court may not admit extrinsic evidence and interprets the plain language of the agreement as a matter of law."