I think one of the defining moments of adulthood is the realization that nobody's going to take care of you. That you have to do the heavy lifting while you're here. And when you don't, well, you suffer the consequences.
We are made weak both by idleness and distrust of ourselves. Unfortunate, indeed, is he who suffers from both. If he is a mere individual he becomes nothing; if he is a king he is lost.
The rationale for loving others is the recognition of the simple fact that every living being has the same right to and the same desire for happiness, and not suffering, and the consideration that you as one individual are one life unit as compared with the mulititude of others in their ceaseless quest for happiness.
Just as you have the instinctive natural desire to be happy and overcome suffering, so do all sentient beings; just as you have the right to fulfill this innate aspiration, so do all sentient beings. So on what exact grounds do you discriminate?
Now this, monks, is the noble truth of suffering: birth is suffering, aging is suffering, illness is suffering, death is suffering; union with what is displeasing is suffering; seperation from what is pleasing is suffering... in brief, the five aggregates subject to clinging are suffering.
Stand up, be bold, and take the blame on your own shoulders. Do not go about throwing mud at others; for all the faults you suffer from, you are the sole and only cause.