By this I mean something is bothering you, perhaps a craving. Is it a good idea to meditate on that craving, perhaps letting yourself observe that it is there and reminding yourself that it will cease? And letting the thoughts come and go on that.
Or would it be more skillful to sit and focus on the breath until you're deep in a meditation anyway, so the craving just becomes one of many thoughts that passes away?
From writing this, it sounds like both approaches are good. But first impressions are sometimes deceiving.