This question has crossed my mind a few times, and quite recently on reflection it came up again.
Why is it that we rarely value the worth of our efforts?
By this I mean, why do people often have difficulty in valuing their own work, contributions, sacrifices and in many cases, themselves. Yet, many are quick to praise similar work, contributions and sacrifices of others.
An example is that I don't see my work as a teacher as being of any value, I am not really fussed about my PhD and the published papers, don't accept compliments well, and even (as some may have noticed) don't feel that I am a particularly good contributor here or on my other SE sites, and as for my own self-value, I literally don't think about it. But will seek to praise others on their good work etc (note, this is strictly an example)