I'd like to say that the original poster pretty much hit the pain that is moderating on the head. I've moderated one large-ish forum before, and adminned another. It is NOT a forgiving job: you have to deal with a lot of complaints and issues on your own free time, not to mention (and I apologize for sounding cynical, but this is the truth as I've experienced it) some individuals who are more interested in you because of the power you wield than your qualities as a person. Also, let's be sure to include the sorts of things Peaches mentioned in the first place - you MUST treat everyone fairly, including friends, and fairness includes enforcing rules equally - no special treatment. The requirement to be on even better behavior than normal is another thing - you have to keep your guard up a bit at all times and THINK about what you post before you post it a heck of a lot more. There are a few things I've already said on the IRC or on these forums that, while not against the rules, I would not say if I was functioning as a mod. You just have to be careful that you put the right public image forth - when you're staff for any site, you are a representative of that site, so your behavior must be held at a high standard. All of this isn't even going over everything..
The hard work it takes to mod or admin is no excuse for an abuse of power, and yet there are a lot of instances where moderators and admins take flak for things that are blatantly NOT abusive of power - usually just aspects of doing their job. One thing I used to see so much when I used to mod, and I am aware happens in every community, is people getting upset about a rule that "should" or "should not" be in place. The thing is, moderators don't really have much of a say in that in most communities, and sometimes even some admins do not. Part of the job is to enforce the rules, whether or not you agree with every single one - and in a community with very many rules at all, anyone is bound to disagree with a few.
So be civil and polite to your mods and admins - they work hard in what can be a rather thankless job. Now I can already hear the objections from some - "Well, in ANY community sometimes staff can get out of control." I agree. But being polite and nice is still the best way to do things, and more importantly, it is the right thing to do. If folks do think a staffer is somehow out of line, it is good to think about it twice. Then think about it three times. Then think about it yet again. If at that point you're still sure you feel that way, then whatever you do, DO NOT post about it publically. Take it to PM, and if you're given flak, go up the chain of command if you have to in order to explain your grievances. Just don't make a recommendation as to what punishment may be in order - staffers rarely like that. At all times, remember that taking major complaints public normally results in a complete fiasco, which serves no purpose other than to inspire chaos and frustration, whether this is the intended purpose or not.
*Cough* All that wordiness through with, be nice, be polite, be happy.. and be thankful for the folks that give their time to do this stuff for us. The vast majority of staff in a good community (having lurked for awhile unregistered, and yet still being around, I'd have to say this is a good community) just want to do their best to help, and it is out of a sense of debt to the community that has treated them well and/or a simple desire to help.