I think they caused the collapse of the Roman empire. Think about it: you grow up in a agriculturally-rich warm country, full of figs and oranges and quinces and cherries, and then you get posted for a 20-year tour of duty to Britannia, where the nearest things they have to fruit are crabapples, gooseberries and rhubarb. Wouldn't you want to bunk off back home?
Rhubarb is renowned for two things: being a laxative, and being poisonous. Roots full of quinones, and leaves full of oxalic acid. Yummy yum yum. I don't know how, but instead of being adopted into the Poisoner's Encheiridion as a dandy way to off recalcitrant great-aunts, people decided to eat it and pretend to enjoy it.
I say pretend, because I firmly believe that nobody does like rhubarb. It's like that revolting green stuff in California that tastes of cheap soap. People pretend to like it, in a kind of "Go on, eat another mouthful, you'll throw up before I do" bragging contest fashion, like eating sushi or swallowing live herrings, or perhaps they've had their palate surgically removed.
Anyway. Back to gooseberries. I have just over 700g of them in the freezer now, having just stripped the bush and scratched my hands and arms to buggery. Still, that's just part of the wonderful experience of loving stgpcm. He likes them, you see.
Renewed contemplation in the light of comments: Evidently I'm wrong - people do like things that have to be cooked with oodles of sugar. But why? Perhaps it's a sourness thing. Jus loves lemon juice to the point where the bottles I buy for cooking with tend to empty themselves mysteriously, often with a Tabby Man sitting by and licking his whiskers and trying to look innocent. Me, I like gherkins and sauerkraut and vinegar, but lemon juice is beyond my tolerance, at least neat. Perhaps that's why I really don't like sour fruit.
But - OMG sushi? fishewfishewfishandrawewewewewewrawfishe