Why might some people consider themselves unlucky, but others consider themselves lucky? ?

Unlucky people miss chance and opportunities because they are too focused on looking for something else. e.g going to a club and trying to find a partner but miss opportunities on finding good friends.

People that are lucky are more relaxed and open to whats going on around them. They're not focused on a single task meaning blocking everything else so much they miss on an opportunity.

Hope this helps