The single biggest challenge I seem to face on a regular basis is best summed up as “ego-driven planning.” If I’ve got something coming up that I’m planning, let’s say a public speaking event (which happens often enough), my mind goes wild in meditation. As soon as I hit the cushion plans of how the talk will turn out, how I’ll be regarded (usually well…I don’t have too many negative thoughts), and so on. Yes, I can bring my attention to my breath, but most likely when my thoughts arise again, they’ll be about the same thing. This will go on for a day or two, then it lessens and more regular random thoughts will arise as usual.
Honestly, it’s not a huge deal or keeping me from meditation, I just find it somewhat amusing most of the time.
The more pernicious challenge that comes up for me, though with less frequency, is shame; usually body-based, but at times about past behavior. Again, I can bring my awareness to an object of meditation and remain reasonably concentrated on it, but this one isn’t as amusing.
So, looking as objectively as possible, my mind seems to want to go to two different places, dreaming of how great things will be in the near future and feeling bad about things in relatively distant past, or beating myself up about my body.
Really it’s just chatter, but yes, it takes some extra concentration to move on when any of these things appear in conciousness.