Beer (and wine) has to be really sweet at the start of the fermenting process, because that sugar is what feeds the yeast. If you don't add any hops, then the resulting beverage tends to be malty sweet and very one dimensional. The hops cut down and balance the sweetness.
Same. I don't get why people are so crazy about IPA, or any strongly-hopped beer style. And why Guinness and Kilkenny are the only two British or Irish beers sold here (Kilkenny is good but it gets old drinking the same beer all the time, and Guinness only works for me when it's on tap).