Whenever I prayed, it was always done consciously and ostensibly to another person -- a higher, spirit person -- called Jehovah. The subject was always something about me, even if it was for someone else. If I prayed to thank Jehovah for my meal, it was about me. If I prayed to ask Jehovah to help someone else, I would perhaps feel guilty if I did not do so even though I believed Jehovah already knew what was needed, and thus it was about me. If I added at the end about the kingdom coming as in heaven also upon earth, I did so because I believed I should and I wanted the new system, and thus it was about me. All of this, every shred of it, is conscious effort and ultimately self-centered, and this carries a negative connotation and guilt to the god I'm praying to.
When I meditate, I usually close my eyes. Sometimes I open them. I focus on breathing. I count my breaths. In a few minutes, my mind and body have calmed down. I feel a smile. I feel my place in the space where I'm sitting, and I notice things. I at first try to squelch all my thoughts, and focus on breathing. At some point though, I let them off the leash and my thoughts go absolutely wild. Then I bring them back in and focus some more. All of this is ultimately self-centered, except there is no guilt to that connotation whatever. It's mindfulness, really. Indeed, I am quite happy to be myself.
A final note: If I am in a group that insists on having a prayer before a meal, I have noticed that I survive the night perfectly in tact no matter what it is I'm thinking of during the obligatory prayer. No lightning, no leprosy. Hilarious.