White and un-toasted. Add the mearest smear of mayonnaise, a hint of salt and white pepper, cut the crusts off, and then cut each round into three rectangles to make finger sandwiches.
White bread, untoasted, thin sliver of marg, feed them to your auntie with weak tea in a china mug and, for dessert, get out Mr Kipling's French Fancies or a couple of slices of Battenberg. Make yourself a few ham and cheese butties with a packet of pickled onion Monster Munch and a glass of crap pop (probably lemonade).
I was like this when I was younger. Absolutely hated them. Then my taste receptor that made them disgusting just kind of switched off gradually over time. Apparently this can happen from middle age onward. Maybe wait a while and try again someday. They're also better with salt.
I'm approaching middle age and still feel this way.
I've never actually found them disgusting, just that they seem to suck the flavour out of anything that's next to them. So many nice experiences eating food have been lessened by including cucumber.
That basically ties in to your last point. They might be fine with enough salt, but they are almost never served that way.