Unlucky....i should say it depends on lot of things, but i believe that the most of "unlucky" things happen in our life because we want to think so. Sometimes we think so negatively that we look like unlucky people. But trying thinking that sth you didn't like happen because there's another better opportunity...sth good will happen, just believe in it. :)

that's our phsychology. we can't always live happy and lucky. it gets boring. so the life seems always black'n'white for us.

 Karma.

Probably forgetting the basical and important things of our life will make us unhappy.
Family, friends,culture,money, love,endevor,work, all these are basical and important in our life.
If a person have fotgot these matters, he/she will become unlucky(miss the chances), I think.