Ofcourse, this is only in the specific context of breaking addictive bad habits, not in a general sense. Allow me to elaborate...
Say you have a very bad habit of day dreaming for hours on end, or perhaps opening facebook to send message to a friend but somehow ending up scrolling through the feed for god knows how long - and you wish to break these bad habits. The usual mantras include "remove temptations", "focus hard", "one thing at a time" so on and so forth. Adding to this long list is my own (soon to be trade marked) "Don't say no, say later!"
I know from experience how hard it is to decline yourself the pleasure of said temptations; mostly you just end up doing them without even realising you're doing them! How do you apply this mantra then? Simple, do not decline yourself, just put a pin in it!
For example, when I am meditating (and other times as well), random stories of past/future and infinite what-ifs/could-bes plague my thoughts. And they are incredibly interesting in that moment, ironic given how I don't even remeber them later on. Anyhoo, once I feel myself being dragged into this pit, I just tell myself "Hmmm, this is interesting, I'll think on it in depth after my meditation is done" and continue on. In rare cases where I do remeber what I was thinking about, it ain't interesting no more - mostly I just forget about it.
Another example, when I am working on some code and encounter an error, go look it up on google and oh - what's this? A new update to.. wait! I'll just keep a tab open for with that link and come back to it later and read properly; for now, back to work. Easy peasy.
So, next time you feel yourself acting out a bad habit: Don't say no, say later!