"Should I be a Mod" decision tree:
* Is there a pressing need for a new moderator?
Yes: Continue. No: End
Explaination: If there isn't a need for someone else, why add one? It's just going to add complexity
* Is the job one you are qualified *and have time* to do?
Yes: Continue. No: End
Explaination: If they're looking for a moderator, it's to take a load off. Making them train you adds to the load, not decreases it
* Are you going to have to deal with morons that you don't have the time or patience to deal with?
No: Continue. Yes: End
Explaination: Being a mod means that you will always have someone who thinks you're doing something wrong - either by being too harsh or by not being harsh enough. Plus you can't just ignore the jackasses, because - unless you're going to lower the banhammer - they're a member of the site and entitled to raise issues to the moderators as well.
* Are you going to be able to act with the highest ethical standards, both by recognizing that your status as a moderator means you no longer represent just yourself but the entity you moderate, *and* not using your moderation powers for anything but the duties you have agree to do?
Yes: Continue. No: End
Explaination: If you see an off duty police officer screaming obscenities, you think "that member of the police is wrong", not "that person is wrong". You wear a badge, you represent that entity, for good or ill - which means that the other mods represent *you* if they do something stupid. Additionally, if you use your powers for evil, you will not only lose them, you will be reviled much more than if you were just a garden vareity nitwit.
* Do you have the respect of a majority of the entity's members?
Yes: Continue. No: End
Explaination: No one wants an idiot in charge, and raising an idiot to the level of moderator raises questions about the judgement of the moderators as a whole. If people, in general, think there are imbeciles on the mod team, they're not going to feel any desire to go to the mod team to deal with issues, and will likely leave or try to deal with problems themselves.
* Are you a fucking moron?
Yes: Continue. No, seriously, continue. Nag and nag and nag, because you'll wear them down with time! They'll see what an asset you'd be if you just bring it up at EVERY POSSIBLE OPPORTUNITY!
No: Either throw your hat in the ring if they're soliciting new mods or wait for them to approach you - and don't get butthurt if they don't. You're not the only qualified person out there, Mr. Egomaniac