I'm going to say this again--security is a big deal; it's a big deal regardless of the size or nature of your organization. Whether you are an international organization of 20,000 people or a small business of 10 people, if you discount the security and integrity of your systems, it's not a matter of if you will be compromised, but when.
Now, I'm not trying to fearmonger, I'm simply stating the facts--there are parties that will compromise your system for no reason other than the fact that they were able to do it. As an administrator, it is your job to do everything within your powers and abilities to keep those parties from infiltrating your system.