Warning: venting ahead!
I am incredibly irritated. Recall I sold a bag and the buyer used an e-check instead of a credit card? Well, I don't know why but every e-check transaction I've had has been a pain. So I suspected I'd have issues with the buyer. I hoped I was wrong but I wasn't.
The e-check took the full 5 days to clear. On day 3 of that time she sent me a nasty note asking when I was going to ship the bag. I gritted my teeth and sent her a pleasant note back saying that because she used an e-check, the funds had not cleared. But I assured her that I would ship the bag within 24 hours when funds were received.
Once the check cleared, I packaged up the bag to ship and found she has an invalid address. I messaged her about this and asked her to change her address. She told me to change it.

I explained I can't make any changes to her address because I can't know her correct one (duh!) and even if I did I would lose seller protection. She then asked me how to change it. Despite not being her mother, her keeper or an eBay employee, I sent her directions. Third round of messages: she says that she still can't figure it out and sends a completely different address telling (not asking) me to change it.
I REPEAT for the umpteenth time that I can't change her address. This goes back and forth a few more rounds over a couple of
days with me ultimately suggesting she call eBay for help. She doesn't want to do that. So, finally, I advise her that that if she didn't have a viable address in eBay by 10am today, I was canceling the sale. At this point I didn't know if she is dense, rude, a scammer or all three. Either way I didn't want to deal with her. This was just too much messiness and hassle.
10am no address is updated. I cancel the sale, refund her money (automatically through eBay) and send her a pleasant note advising her of my actions. That leads to her sending a flurry of angry, profanity laden messages accusing me of bad customer service and of swindling her.

I don't bother responding to any of them. I simply report her messages to eBay and block her from bidding on any of my items ever again.
This is absolutely ridiculous. Buyers have a responsibility to know eBay procedures and policy before they buy. I'm not a store. I'm not your mommie. I don't want to hand hold you. I don't want to walk you through steps on eBay. I don't want a simple transaction to take 8 days. And I certainly don't want to be cursed at.
This is also why I get my dander up when I see people posting in various places on TPF about proudly being being bad buyers and expecting the world from sellers. Everybody needs to be a grown up - polite, considerate and fully capable of using the tool that is eBay. I will never understand the sense of unbridled entitlement that some people have.
Grrrr!!!!