I have a recipe for liver with oranges in our house cookbook. It's pretty good, but requires good, juicy, tender eating oranges. The typical California/Florida navel oranges just don't cut it; they're only usable for juice. So, the last time I made it, a week or two ago (I'm just now finishing up the last of the leftovers because I'm the only one in the house who likes liver), I tried buying some Florida-grown mandarins instead in the hope that they'd be juicier and less tough.
Holy CRAP, Batman. I don't think I've ever before had any kind of citrus fruit — hell, any fruit, period — as fibrous or as full of seeds.¹ Trying to eat these things, even cooked, is like chewing a mouthful of orange-flavored plastic bags, except that the plastic bags have less seeds. You've seen "seedless" oranges and tangerines? Well, now I know what they did with all the extra seeds. I'm not sure I'd even dare run them through an electric juicer. They were so full of seeds it was literally difficult to cut them into the quarter-inch slices called for in the recipe, because I couldn't find a cut line that didn't run through half a dozen seeds.
Needless to say, I won't be buying these Florida mandarins again. I suspect this is another case of foodstuffs bred to ship well, rather than to actually be edible.
 Well, OK, I'll concede pomegranates have a (slightly) higher ratio of seeds to volume. But I don't eat pomegranates. They're nasty.