Ah, bit of a lovely nostalgic moment - that was me only a few months ago. Now I don't need to think about un-clipping. Just need to remember to drop a few gears when coming to a halt.
Yes, standing up is a different game altogether with clipless. Also you'll start to feel those hamstrings a bit, which were a bit useless on flat pedals.
Would I go back to flat pedals? Like driving a small engined car after having some decent power under the bonnet - just seems pointless.