Commentary on Meditations: B10:19-22

What sort of people are they when eating, sleeping, coupling, shitting, etc.? Then what are they like when given power over men? Haughty, quick to anger, punishing to excess. And yet just now they were slaves to all those needs for all those reasons: and shortly they will be slaves again.

What universal nature brings to each is brought to his benefit.  The benefit stands at the time of its bringing.

'Earth loves the rain, the proud sky loves to give it.' The whole world loves to create futurity. I say then to the world, 'I share your love.' Is this not the source of the phrase, 'This loves to happen'?

Either you live on here, used to it now; or you retire, your own decision to leave; or you die, your service done. No other choice. Be cheerful, then.

If you've ever taken a public speaking class, you may have been taught a few tricks to get over the butterflies or the feeling of anxiety.  One of them is to imagine the audience in less flattering circumstances - being naked, for instance.  Supposedly, that helps some people in taking off the edge.  Similarly, Marcus advises us to imagine people as just normal people who do normal things: eating, sleeping, having sex, going to the bathroom.  All of a sudden, their haughtiness (pride, ego) isn't so formidable; their anger is comical; their power to punish is diminished.  They are slaves to eating, sleeping, pooping and soon they will be a slave to death.

In chapter 20 of Book 10, this is a theme Marcus oft repeats.  Whatever the Universe creates (and all the byproducts of it), the benefit is self-evident.  It's kind of a cryptic passage, but falls under the domain of the discipline of desire.

Similarly, chapter 21 of Book 10 falls under the category of Universal nature.  Things flourish on the earth when it rains and the sky's purpose (one of them) is to send rain to the earth.  Things are in harmony.

Live in the present or not at all.  A bit extreme, but the point being perhaps twofold.  1.  Love your fate - love what is happening now.  In some form or fashion, it benefits you (makes you a better person).  2. Complaining accomplishes nothing.  Contentment with the now (or at least endurance) or nothing.

(see also Citadel p. 141, 230)