There's three possible causes to you loneliness
-Seinfeld syndrome. Are you turning girls away because they have a mole on their chin? Because their accent is too thick? Because they slurp their soup? If you're too picky, you won't have any success, period. There may be 3 billion women on the planet and one who's a perfect match but realistically, how many can you date? Give the girls a few strikes before kicking them out.
-Bad luck. Some guys meet great women no matter where they go. Statistically speaking, that means some guys never meet great women no matter where they go. What's a rough estimate of how many women have you dated? How many relationships have you had? Very, VERY few people meet their soul mate on the very first try. I expect I'd have to date at least 100 women, (and meet hundreds more) before I found someone compatible.
-Looking in the wrong places. Bars and clubs are for hooking up. The gym (with a few exceptions) is full of desperate girls two days away from quitting their diet. Think about places where smart people gather. I find a book store population's intelligence to be marginally higher than average.
Let's look at the turn-offs you listed.
1) Stupid or irrational. Stupid I can understand. It's no fun to be around dumb people. But some just aren't book smart. You can tell when someone is sharp but didn't pay attention in school. Pi will be rational before women, I'm afraid to say. They think with their whirlwind emotions. Just accept the least irrational girl.
2)Randomly crazy. Ugh, I know. They devolve before your eyes back to stubborn, screaming 5 year olds. And they say BOYS are slow to mature. This falls under irrationality, so see above.
3)Physically unattractive. You need to overlook the little flaws. I used to think my ex-girlfriend was physically a 5 out of 10, but her looks became endearing over time. Compromises must be made or you'll be hung up about her looks forever.
4)Childish. Again with the maturity. See Looking in the wrong places.
If you go overseas, have fun. If you go to an Asian country, you'll be a celebrity, and this may be the only chance you get to leave the country for a while. The women are similar no matter what the culture, though.