in the various positions in the IT industry we all have a specific job to do with various tasks. we don't always do them as well as we could. usually it boils down to someone doing the bare minimum for a variety of reasons and something ends up breaking.
there are different reasons why things might not be done as well as possible. maybe the deadline's fast approaching and you just need something to work. maybe you've not got enough budget. maybe your bosses are just jerks and even though you tell them what you need to get it done right, they ignore you and force you to produce sub-standard work.
the resulting fail will sit in the background for some time until a random occurrence triggers it. by chance something goes wrong and then everyone breaks, and you're left holding the bag. sometimes that means big hassles and wasted money. sometimes it means you get fired. so when you do have the chance, take the time and do it right.
as far as security is concerned this principle affects everything. there are lots of things you can do to secure any given system. the more you do, the less likely it is that the one attacker you were working to stop will be successful in his or her objective. this applies to everyone in the IT field: programmers, admins, NOC, QA, analysts, managers, etc etc. if you do it all right the first time you won't be left with the bag.
so for example. if you work for a large mobile internet service provider and it's your job to set up the service paywall, don't skimp on anything. make sure it's as secure and reliable as possible and don't trust anything to chance. the one person who figures out that way for everyone in the country to get free internet could bring on considerable strain (financially and otherwise) to your employers, and they won't be happy with you.
or if you run the large systems which are targeted by drive-by botnets as command and control machines or injection points, do your jobs, people. apply the latest security-tightening patches. use mandatory access control. use chroots. use separate users for each service. remove the need to log in as root wherever possible. add intrusion detection. keep up with patches! do you know how much of a hassle it is to clean up and replace systems that have been owned en masse just because you allowed a simple shitty buffer overflow to execute?
and programmers, come on. you're never held responsible for these problems. it's always the other groups which are used as the example and who look foolish because of your crappy, insecure code. the code runs on their systems, so the perception is it's their fault they got owned. but they didn't write that shitty file-uploading php script, you did. you let the bot herders in the front door and made it that much easier for them to expand their attack into the network. congratulations, homie. yes, the admins should have tightened security around php to account for unexpected holes, but you shouldn't make it easier for the attackers either.
and firewall dudes: how hard is it to friggin download a malware watch list and block bad domains/IPs? you're responsible for both the servers AND desktops which are affected by worms/trojans/etc. you know how to tighten these boxes down and tighten up the network access, so do it already!
you're saving yourself work in the end. how many of us have been caught in a tight deadline when suddenly all work has to stop to deal with the intrusion and see how far it got? do you have the spare boxes and cycles to deal with that? how is it affecting your bottom line? your sleep schedule? in the end it's the executives and managers who need to be more proactive in enforcing these trends in the rest of the work force, because if they don't force people to then nobody's going to take the extra time. create a culture of polished work and everyone should benefit.