Like a vessel's wake, a signature is evidence of your presence. In most commercial scenarios, a signature acts as an identifying mark as well as proof of consent to a document's terms.
Your signature carries legal weight. When you sign a document containing terms and conditions, the law will generally assume you understood and agreed to the document's contents. An after-the-fact assertion of having not read the fine print is about as helpful as an outgoing tide. While there are always exceptions, the courts take a very dim view of efforts to avoid a contract signed by an individual who later claims that he or she didn't know what was being signed.
For example, an arbitration panel held a vessel owner to the terms of a salvage contract, finding it unreasonable that he had not appreciated what he was signing. A businessman who signed a shipyard repair contract waiving certain claims against the yard was subsequently prevented from suing the yard because he had "read and signed the agreement without expressing any reservation."
Among other things, a hastily scrawled signature can bind you to terms and conditions which can waive your right to a jury trial, subject you to fees if you pursue litigation, and/or otherwise force you to resolve disputes in some faraway place. No matter the document, prior to gracing it with your signature, take the time to review its contents so you understand the nature of its obligations. If you're not happy with one or more of the terms, try to negotiate an acceptable resolution. If circumstances don't permit you to rewrite its provisions, step into the hallway (or onto the deck) and call your attorney. Your admiralty attorney can likely recommend alternate language or an appropriate objection to accompany your signature.
There's a lot of sea spray that comes at you in life, and there's a tendency to sign things quickly in order to move on to the next issue. A prudent mariner, however, understands the importance of a signature and, unlike a vessel's wake, a signature doesn't disappear.