The meaning of this quote is that sometimes we could have very good reasons to be happy but it is difficult to see them, either because we do not know wehave themor because we have not discovered them. As a result, wecan feel a little upset or disappointed- Anotherpossiblemeaning is that we have great and positive strenghts, but we do not appreciate them or we have not realized about them.
When we say complete subject, this is what is being talked about in the sentence including its modifiers, and the complete predicate includes the main verb and its modifiers as well. In the given sentence above, the complete subject would be "He" and the complete predicate would be "<span>had no help with the project." Hope this helps.</span>
