I have what most people would call a generally 'good' life (I think). I am doing well at university, I have good future prospects, I am young and relatively healthy, I have good friends, I have a close and supportive family, I spend time helping others through volunteer work, I am in a hassle-free and good relationship, and I have no financial problems.
Recently however I have begun to feel that my life is more or less a waste of time. Although I have felt this in the past, I got rid of the feeling by doing more (studying more, socialising more, etc) and it went away for a bit. Still, I can't help feeling that unless I do something 'great', there is no point in my being alive. On the other hand maybe I should just enjoy every day as it comes, and ignore the fact that my life is ticking away in a pleasant but largely unremarkable fashion.
Are people's lives only justified if they do something that they and everyone else thinks is extraordinary? Or is it okay just to be mediocre and content? Is it selfish to even wonder this, and should I just count my blessings?