While I'm sure there's assholes on both sides of the buyer/seller fence, ebay has forced order on everyone(good) by making sellers do all the work (not so good). Instead of putting any sort of restrictions/regulations on buyer behavior, sellers had to make all the changes. We now have to do whatever a buyer demands in effect. The listing clearly says to ask with any questions, and NO RETURNS because your ordered the wrong part. Four times someone bought an item, then complained it was my fault it didn't fit their motor and demanded a return. When I told them it explicitly said no returns, they get all pissy and threaten go to go ebay about it. One did. With ebay on my case, I said fine, mail it back and I'll give you a refund when I get it. Nope...not good enough. They wanted me to both send payment for return postage and the refund in advance.
So really the only way a buyer can get in trouble is through a non-paying bidder case. If they're found "at fault", ebay puts a "strike" on their account. Which means virtually nothing. The strictest "buyer requirements" I can set as a seller for that is 2 strikes within 12 months IIRC. A buyer can rampantly scam on sellers, who end up complying since it's way too much hassle to resist, and sellers can get in trouble with ebay very easily. Powerseller perks get revoked, store can be temporairly closed, even suspensions can stem from a single failure to appease the ebay gods.
So here's my 1,2,3's for a good ebay experience. I've played both sides of the buyer/seller game pretty extensively on a variety of accounts.
If you're a buyer:
1. Check feedback. Not just the percent shown next to their name, click on the feedback number and read some of it. Within a page or two any "trends" of the seller should emerge. Slow to ship, poor packaging, ships via super economy snail mail, ect. Many times people will still leave pos but include comments like that. My rule is if the seller is under 98%, I look elsewhere unless it's a unique item, but it's pretty rare there's only ONE person selling a widget on ebay.
2. Read the listing thoroughly. Study the pictures. The "ask a question" button is there for a reason. Never guess or assume anything about the item. Ask the seller. I had someone buy a prop from me, it was a left-hand rotation. I thought that was pretty obvious from the picture. Someone bought it, then got bitchy since they were expecting a standard right hand. If the shipping says "economy", ask what it is. If it's Fedex "smart post", bail. You'll be lucky to see the item within 3 weeks. UPS basic is OK, in essence it's one day slower than regular UPS ground since USPS makes the final delivery.
3.Pay promptly. When you take a long time to cough up the money, sellers tend to be in less of a hurry to mail your stuff out. Paying immediately after buying, or shortly after winning an item makes sellers happy, and it gets your stuff to you faster.
If you're a seller:
1. Clear and detailed listings, but keep it short. Nobody wants to read about some story loosely connected to the item, or a history lesson about it. Avoid technical or trade-related jargon...if needed, put it in laymans terms. Straight to the point. Pictures are an absolute must....and forget about stock photos google turned up. Get several clear, well lit, orthogonal view photos. Top, side, back, and especially a close up of any damage/faults. Trying to "gloss over" damage with photos or the description is almost sure to bite you in the ass later, so don't.
2. Set buyer requirements. By default your listings will be totally "open", as in absolutely anybody could bid. BR's let you filter out any negative feedback buyers, buyers with too many strikes(unpaid items), or buyers with shipping addresses in countries you don't ship to. This keeps a surprising amount of "riffraff" out of your auctions or listings.
3. Shipping. When boxing/preparing your item for shipping, assume it's going to be tossed out of moving vehicles, repeatedly. Don't mail a brick in a paper envelope. Even items you might think are pretty unbreakable, the USPS will amaze you. Things need to be bubble wrapped, padded in newspaper, double boxed if it's heavy. All that, and a prop still arrived with a bent edge and a hole in the box. You're responsible for shipping, and even if the carrier breaks it, it's your problem. Get insurance for anything worth over say, $20 or so, it's only an extra few dimes. Don't use economy services, it's not worth it. The difference between parcel post(7-10 days lower 48) and priority(2-3 days lower 48) is usually only a couple bucks, say $18 for snail mail or $22 for priority. That extra four dollars saves a week in transit, so just charge for shipping based on priority mail. Using priority also shows as "expedited" shipping on your listing, something buyers like to see.