I don't mean to sound condescending, but you mentioned couple of things that made me cringe. Repeating "impermanence" one hundred times while stuck in traffic may help relaxation (even though you could repeat "induction" or "crystallisation" with the same effect), but I don't think it changes your way of looking at things. What would is a big topic for discussion.
I should clarify, as there is a misunderstanding here. I meditate while repeating the word "impermanence" - on the out breath, on the in breath, on both breaths, at whatever cadence I feel like (have tried all 4 versions). It seems to imbed a sense of the impermanent nature of things, at least for a while (a week or so after one session).
One really big Buddhist concept is the idea of being one and the same with everything else. The same way the waves in the surf are part of the ocean. You are not separate from the person next to you, Fat Cat, me, the house across the road etc. Thinking about the world radically changes the idea of compassion: when you get the "oneness" you will be hurting about the person's misfortune with the same intensity as you will about your own. His pain - your own.
Haha, not an easy task by any means :)
One Russian author I cherish a lot once said: the best advise to the youth he can give - work on your full lotus position, it will be very, very useful later. Implying being able to sit Zazen, of course. Try find that in the self-help books! Another thing he said in one of his books - chasing happiness for yourself is similar to the arrow of a compass to point at itself. The easiest way to find happiness is to give it to someone else. One caveat - you cannot be choosy, you have to be doing it to everyone.
Anyway, this is a very rudimentary expression of some great ideas. There are many ways to sing the proverbial cat, and Buddhism is only one of them.
Sorry to get things out of order, was trying to respond to each item. I can sit in full-lotus, but almost never do. It does seem to make meditation deeper. And I've heard that about happiness, there's a quote I like:
"Happiness is like a butterfly. The more you chase it, the more it eludes you. But if you turn your attention to the things, it will sit quietly on your shoulder." - Ralph Waldo Emerson
Bram, meditation is an exercise in attention. Most known being breathing meditation - you know it, of course, where you bring your attention to the air moving in and out of your nostrils. Your mind drifts away, you notice it and bring the attention back to it. This allows to calm (sort of) the mind, get rid of the myriads of thoughts that usually swarm inside our heads. As the result the mind stays more attentive during the day. Moreover, long term effect of meditation is a different perception of reality, where you begin seeing case and effect more clearly, as well as impermanence etc. That's apparently was the Buddha's path. Though who knows.
Meditating "on something" is a contradiction of sorts, as when you do that there is no attention as such, but a lot of contemplation. Which can develop into a full blown fantasy. Tibetan Buddhists (the branch, in my opinion most deviated from the original ideas), for example, meditate on emptiness, compassion and what not. But then how can you picture emptiness? The only way is to create some picture of it in your mind, which is bound to be artificial, and develop your "understanding" of it. Doesn't make much sense to me.
I would have to disagree on a few of your points. I don't know about meditating on emptiness, but I've read the procedure for doing such things and it seems reasonable. As for compassion....if you just focus on kind thoughts towards yourself and others (google "metta" or compassion meditation for an outline), that definitely works.
For example, you can think "Bram is a cunt" and see how it makes you feel, or you can think "I hope Bram has a good day" - I don't think you have to be super clued in to see one adds anger and one feels good.
Agree with the rest :)