You should probably have a different password for every relevant/important site/service you use. I, too, have a throwaway pw, but for the important things (Twitter! Facebook! Bank! Gmail!), I have a standard password that's really long, but memorable for only me, and for each one of the different sites, a unique "key" in the middle. So, to use the classic XKCD example http://xkcd.com/936/ if my standard password is "CorrectHorseBatteryStaple", the Twitter password might be "CorrectHorseRetweetBatteryStaple" and Facebook might be "CorrectHorseLikeBatteryStaple", and so on.
Take an empty toilet paper tube, put a long string through it, and wear it as a necklace. When people ask, "So, um... what are you?" Say, "I'm out of toilet paper." I like to think this would be taken as gently mocking the notion of Halloween costumes.
As someone with experience working on the other end of this, I have a faster, less soul-eat-y, solution to customer service hell. I wish I could remember where I got it (because I didn't articulate it this way first), but here goes: If you get frustrated, ALWAYS ask the customer service person, as kindly as possible, "What would you do if you were me?" This does two huuuuge things for that PERSON. 1) It gives him/her agency and power; you've given him/her permission to explain to you as best as he/she can steps to the quickest and best solution the company can offer, which really is that person's goal. Really! 2) It forces that person to empathize, even if only for a split second. Remember that this person likely speaks to many angry/frustrated/confused/stupid people over the course of a day, so approaching this encounter in a spirit of cooperation helps him/her understand that you are not one of the cretins. You get it. You're just trying to see that things are made right. But if you just want to stick it certain companies, and don't care about things like kindness and such to ALL people, then by all means follow this advice.