The Decline of Must

Something you might to have noted

about the use of this short but heavy

prescriptive word connoting obligation:

at least in spoken English, it is not used

as much in these more permissive times

because it is not as good a fit for us now.

And so it has been replaced by words 

that soften the force of obligation:

the somehow friendlier "ought to"

the implicitly more personal "have to"

the breezily advisory "got to"