Latest frustration with simple delivery is eBay forcing 'combined' delivery on sellers if a buyer purchases more than one item from you. I'm selling a few gaming mice, a few monitors and some mousepads on eBay. Someone bought both mousepads and a mouse from me - and eBay has put it as a 'combined' delivery.
The mousepads are flat pads, they cannot be rolled otherwise it breaks the pad - so the pads have a dedicated square, flat box to support all of them. The mouse, obviously, is in a box. The two items quite literally cannot be combined into one parcel and eBay support weren't super happy about my suggestion to just parcel tape the mouse to the front of the mousepad box 'in case it fell off'. But they weren't willing to split the combined shipment up either!
The whole 'simple shipping' thing has just caused me so many more unnecessary headaches, I wish they'd just made it optional. Let people who want that side handled for them have that available - but I like to be able to control my shipping, the type of courier, the service, splitting parcels where necessary etc.