You need to know the difference between trademark and copyright.
With trademarks you can hold the rights to short quips like "That's hot!" or "You're fired!"
With copyrights you cannot. You cannot copyright short titles or catchphrases.
However a trademark is difficult to get and takes up to 20 months to have it registered (not to mention costs, $500 +).
On the other hand if something is public domain you can use it as much as you want.
If you put an ambiguous catch phrase on your shirt that would be fine, but copying the likeness or image of somebody else is illegal without proper permission (infringement).
An ambiguous catch phrase like,
"YOU'RE FIRED!"
might be okay.
That being a generic, yet well recognized phrase.
Of course if you put the Trump's image on it you'd get in trouble.
If you took a picture and altered it enough it could be considered as artistic imagery which may make it okay to reproduce.
Another thing about the generic catch phrase is, anybody can copy it. The only protection you'd have (assuming you don't register for copyright) would be the "unique" spin you put in displaying it.
Prepare for tomorrow today because tomorrow will quickly become today, and you want to live today.