I am not cynical here, I find lesswrong very entertaining to read for similar reasons to I regularly read research papers on things I'll never need in my life for fun.

I cannot possibly be alone - just ask anyone what happens when they want to quickly check a random article on Wikipedia or even worse TvTropes and end up spending an entire day on the site, learning minutae of things they have no use for whatsoever.

XiXiDu's and David_Gerard's responses suggest there's plenty of people who see lesswrong the same way.

I go back to chans every now and then, but it tends to get boring after a few days.

If you want helpful advice (wrt "sucking at rationality"):

• For everyone's most popular problem of akrasia, "Getting Things Done" by David Allen is way better than reading lesswrong ten times over again. Most of other books on the subject are crap, but this one is definitely pure gold.
• For accurate judgments there are books like "Judgment under Uncertainty: Heuristics and Biases". This is even easier, since you don't seen to sift your way through tons of garbage book.

One super-simple and very practical exercise I recommend is - every time you go shopping try to estimate cost of your shopping basket before you checkout. You'd be surprised how far off and how one-sided your estimates will be the first few times. Since everybody shops a lot it won't take you any extra time, and that's actually a pretty useful instance of more general skill of quick estimation.