FWIW, with all the changes that eBay has made in the past year to add features, most of them default to "On" without the seller even knowing about it. The other thing that annoys me is that they no longer seem to have a "save these settings" option anymore, so if it slips your mind, you will put a subsequent item up accepting offers when you didn't mean to. The same thing happens with their "Global Shipping" option. This one bites me from time to time, as I don't like shipping globally anymore - I've just had enough bad luck with International buyers in the past.
Honestly, the thing that bothers me most is that they added an "accept offers" option for auctions. Who would put something up for auction if they are going to be accepting offers for it? Wouldn't you just make your "Best Offer" the opening bid price (assuming you don't stifle it with a Reserve price) and be done with it?