I think you should write out your note, OP. Explain exactly what you're feeling, and why you think you feel that way. Do not make it nice. Make a separate one dedicated to each family member or coworker or ex who's pissed you off or hurt you. There's no need for passive-aggressive subtlety with a note like this, be as blunt as you want to be. Use lots of exclamation points and underscores, free and excessive use of red sharpie. Decorate the margins with skulls.
The fact is sometimes it really is another person's total fault. You may have been taught to examine your own role when something goes wrong, and that blaming others is always wrong. Well, it doesn't usually solve anything, but sometimes it really is that fucker's fault. So don't feel guilty about blaming them.
So then when you're done, re-read it, and then write another note that is even more blunt and explicit. Do it a few times. Besides the obvious venting, you might get some new insight and perspective, and remove some of those guilty barriers to telling people to fuck off.
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Do we (bluelight) have an unofficial IRC channel? Is that always manned?
I'm just wondering if it's an option for OP.