Enterprises of great pith and moment?

Answer 1

This is from Hamlet's "To be or not to be" speech.

Thus conscience does make cowards of us all;

And thus the native hue of resolution

Is sicklied o'er with the pale cast of thought;

And enterprises of great pith and moment,

With this regard, their currents turn awry,

And lose the name of action.

This could be rephrased a bit:

That's how conscience makes cowards of us all

And how our strong resolve

Fades as we think about the consequences

It's how monumentally important plans

Being closely examined, are derailed

And don't actually ever happen.