This is the single biggest problem with contract drafting, and lawyers do it as well as lay people - to read into your words what you think is there as opposed to what they actually say.
The law sometimes gives a contracting party a way out by allowing you to admit evidence in a dispute over what the parties truly intended if the language reads ambiguously, assuming the language is merely ambiguous and not plainly and incontrovertibly against you. But, trying to salvage a contract in this way is like playing out a desperate last act because, by the time you reach that stage, you will already have a losing situation on your hands. Even if you win such a dispute, by the time it reaches litigation, you likely will have already lost economically on the deal in most cases.
The lesson here is not necessarily, "always use a lawyer" (though you should if you have a lot at stake in a particular contract) but rather, "read your contracts carefully and literally before signing." A good lawyer will do this, as will a seasoned executive or contracts manager (or founder, for that matter) who is experienced in dealing with contractual issues or who otherwise has a knack for this sort of this (some founders do have such a knack, most don't). Never simply assume that the language is what it appears to be at first glance.
The law sometimes gives a contracting party a way out by allowing you to admit evidence in a dispute over what the parties truly intended if the language reads ambiguously, assuming the language is merely ambiguous and not plainly and incontrovertibly against you. But, trying to salvage a contract in this way is like playing out a desperate last act because, by the time you reach that stage, you will already have a losing situation on your hands. Even if you win such a dispute, by the time it reaches litigation, you likely will have already lost economically on the deal in most cases.
The lesson here is not necessarily, "always use a lawyer" (though you should if you have a lot at stake in a particular contract) but rather, "read your contracts carefully and literally before signing." A good lawyer will do this, as will a seasoned executive or contracts manager (or founder, for that matter) who is experienced in dealing with contractual issues or who otherwise has a knack for this sort of this (some founders do have such a knack, most don't). Never simply assume that the language is what it appears to be at first glance.