There is a pop culture Buddhist saying: Don't just do something; stand there! Another version of the idea is "An idle mind is the devil's playground."

One could say that boredom or the fatigue of doing nothing is the cause of some of our problems, at least. But weakening "all of humanity's problems" would ruin the aphorism. Nobody would quote, "About 39% of humanity's problems stem from man's poor performance at sitting quietly in a room alone." It has lost its punchiness. Furthermore, lowering the figure from "all" to "39%" makes us want to know "Where did you get your statistic from?"

We don't have to take Pascal's "All of humanity's problems" literally, as 100%

I have to agree with such a statement. It is indeed difficult to be alone with one's thoughts and nothing to distract from them.

"To The Reader"
Charles Baudelaire

Folly, error, sin and avarice
Occupy our minds and waste our bodies,
And we feed our polite remorse
As beggars feed their lice.

Our sins are stubborn, our repentance is cowardly;
We ask high prices for our vows,
And we gaily return to the muddy road,
Believing we will wash away all our spots with vile tears.

On the pillow of evil it is Thrice-Great Satan
Who endlessly rocks our bewitched mind,
And the rich metal of our will
Is vaporized by that wise chemist.

It is the Devil who pulls the strings that move us!

...If rape, poison, the knife and arson
Have not yet woven with their pleasing patterns
The banal canvas of our pitiful fate,
It is because our soul, alas, is not bold enough.

But among the jackals, panthers, bitches,
Monkeys, scorpions, vultures, serpents,
The monsters squealing, yelling, grunting, crawling
In the infamous menagerie of our vices

There is one uglier, more wicked and more foul than all!
Although he does not make great gestures or great cries,
He would gladly make the earth a shambles
And swallow the world in a yawn;

It is boredom! his eyes weeping an involuntary tear
He dreams of gibbets as he smokes his hookah'
You know him reader, this delicate monster,
- Hypocrite reader - my twin - my brother!

To be precise, he did not say being alone meant doing nothing.
Pascal promoted a severe form of personal discipline. In that key, the message would seem to be that you should too.
But the statement also suggests we can provide something for ourselves that we tend to consider to be only available through others.
A neglected resource.

I see some truth in Pascal's words. If you can't be at peace with yourself, you are bound to cause problems to yourself or others sooner or later.

Blaise Pascal (1623-1662), in his Pensees, writes: "All of humanity's problems stem from man's inability to sit quietly in a room alone." (I would add, DOING NOTHING, which is how I'm sure he would have intended the statement to be understood) — miguel d

Later in life his wife took up with another man, leading the neighbors to gossip about Pascal's triangle.

perhaps