Wow, I'm a terrible person. Don't calculate efficiency, don't measure OG or FG. If the beer tastes good, I did OK.
Yes. I've measured my efficiency a few times to make sure nothing was horribly wrong. I've measured OG and FG for most batches to make sure nothing was horrible wrong. Now, I just drink the beer and enjoy it!
That being said I also think it's very important to understand, measure, adjust, and measure again all of that stuff. Then when you really know what's going on it's a lot easier to slack off and rely on your experience.