An indication of this is when we resent it if the recipient is ungrateful. Such self-denial leads to resentment. If our life is unbalanced then we are busy chasing after only one area of life and all the others suffer. I do not think we can derive enduring happiness from just one part of life, such as work or children. There is much to be said for the Greek ideal of balance.
Workaholics lack the contrast because they do nothing but work.
We need to find a balance. Another vital element that gives us meaning is love - loving oneself and loving others. For many of us it is easier to love other people than to love ourselves. To realise and fulfil our own needs, as mentioned earlier, is part of loving oneself. Happiness, in my opinion, is something that needs to be shared.