Tollorin wrote:
Even though I consider myself as a smart person I'm not very good on those kind of problems. I guess I'm not that smart.

Not necessarily. My mind usually balks at those kind of problems, but I still consider myself smart. Perhaps a better way of putting it is that I feel some pride in my many fine aptitudes, but solving hard puzzles isn't one of them.
Even then, it's possibly more to do with the way I feel about hard puzzles. They annoy me, though I'm not saying there's anything wrong with them. I just dislike their unreal nature (if they don't happen in real life then why not use the time on problems that do?) and the fact that they've been contrived to be difficult (life is hard enough without deliberately making it harder). They remind me of the second half of my school days when they were setting me all this work I couldn't do, revealing my weaknesses and judging me for it. I suppose hard puzzles threaten my self-esteem, because that's got one of its main roots in my intelligence, and by definition "brain teasers" generally challenge intelligence.
Both my father and grandfather had some fairly logical criticisms of the newspaper crosswords they did. They said that the bits they didn't get usually ended up having stupid answers. I don't think it was all sour grapes. I saw those answers too, and couldn't see why they were supposed to be correct.
I don't always pass puzzles by though, and can find them fun. I was considering attempting the "nationality/pet/drink/cigarettes/colour" problem, and was tempted to get my pen and paper, but didn't realise it was allowed, and figured that my short-term memory wouldn't be strong enough to solve it in my head.