I hate the way people think about politics, independent of the ultimate outcome.
But perennial defeat isn't the only reason I hate politics. On reflection, I'd loathe politics even if my policy views matched Clinton's or Trump's word-for-word. Indeed, I'd loathe politics even if I thought prevailing policies were the pinnacle of wisdom. Why? Because I hate the way people think about politics, independent of the ultimate outcome.
I hate the hyperbole of politics. People should speak literal, measured truth, or be silent.
I hate the Social Desirability Bias of politics. People should describe reality as it is, not pander to wishful thinking.
I hate the innumeracy of politics. People should focus on what's quantitatively important, not what thrills the masses.
I hate the overconfidence of politics. People shouldn't make claims they won't bet on, and shouldn't assert certainty unless they're willing to bet everything they own against a penny.
I hate the myside bias of politics. People should strive to be fair to out-groups, and scrupulously monitor in-groups, to counteract our natural human inclination to do the opposite.
I hate the "winning proves I'm right" mentality of politics. Winning only proves your views are popular, and popular views are often wrong.
Last but not least:
I hate the excuses people make for each of the preceding evils. While I'm open to consequentialist arguments for doing evil that good may come, most of the arguments in this genre are deeply tainted by innumeracy and overconfidence. If you calmly weigh the social benefits of political hyperbole, carefully crunch the numbers, and grudgingly and sorrowfully conclude that it's justified in specific cases, I'm all ears. But if you defend hyperbole with casual, undiscriminating delight, life's too short to listen to you.
P.S. While I hate how people act in politics, I emphatically don't hate the people themselves. Politics is only a small sliver of most people's lives, so the apolitical good normally far outweighs the political bad.