When most people here talk about push-ups, it seems that, at least in the beginning, they really plan for it. Like they take one hour or so out of their schedule to sit down and start meditating or introspecting. However, since 4-5 years ago, long before I found this forum, I've been naturally doing very irregularly timed pushups. I don't really plan it, but whenever there's a lapse in time, like when I'm taking a shower, walking or on a bus/train, i find myself either just naturally relaxing and letting my mind wander or introspecting on things I've done in the past. I can do this for 10 minutes or for hours.
Interestingly though, when I try to actually plan a meditation or introspection session, it never seems to work very well. Is this something I should be trying to fix or should I continue the way I always have?
Ray is depends how heavy your mind is leaning on you. Some people need to sit down and face the daemon as a matter of practice, others do it on the fly. If you have a real deep pain, then I suggest tackling the motherfucker from a more practical vantage. Otherwise what you're doing is just allowing it to come, and you seem pretty cool with it; so unless you have more pressing concerns?
The reason it isn't 'working' when you plan a session is because you're thinking in terms of making something happen. That's just what the mind does as it's very results orientated. If you're going to sit, do without expecting anything in return, and do it without deciding what it is you should be doing. Whatever needs to arise does, and even then let it go without analysing.
Lastly, there's nothing you should be trying to fix. Trying to fix is a mind concept, and you can't fix anything with the same tool that caused the malfunction.