Reality is Trumps.

There's nothing wrong with a good fantasy: Tolkien, Gemmell. Pratchett, Adams...
I've enjoyed many varieties.

But I'm not at all keen on mistaking fantasies for reality.
Not even, or perhaps even especially, when the fantasy would be a lot more pleasant than the reality.

God knows 'twere better to be deep	15
Pillowed in silk and scented down,
Where love throbs out in blissful sleep,
Pulse nigh to pulse, and breath to breath,
Where hushed awakenings are dear...

From Alan Seegers' "I Have a Rendezvous with Death", where the speaker has a fantasy he might even turn into reality, did not other realities such as principles, and promises made, already exist.

But what has fantasy to do with CFS, and the daily round of managing it?
For one, for me, it means that I can't use unrealistic projections or undue optimism as means to create or sustain a positive mood.
Grounded optimism, fine.
A view plucked out of nowhere that "everything will turn out for the best."  (or any of its relatives) sounds nice, but with my autistic analytical brain such sayings do not survive critical analysis, and critical analysis they get.
I'll be very happy with any castle in the air whose foundations pass building regulations.

Reality is trumps: two conversations today, one with a neighbour, and the second with the driver delivering my week's groceries, took me to my activity limit for the day, though neither were long or in the slightest demanding.

Extra hours of rest were required, and no wishing or pretending it were otherwise would serve to make it so.

Whatever I would like.

"That which is, is."  Charles Fort.

Very much said in the context of attempts to set-aside reality for some preferred alternate world-view.

My limitations today are what they are, likewise pains and aches.

I start from here.  I wouldn't suggest anyone else does, unless they have to!