Normal is more like 50 and up, due to meter considerations. Some say that something like 50 is actually a good number, but I attribute it to the meters.
From what I have read, some of the meters falsely lower the numbers at the low end so that people won't get complacent and hypo themselves. So according to that theme (which is kind of a mystery - I don't think they spell it out in the manual or anything), what is actually an 80 would read 50 on the meter (supposedly they run them 30 points low).
Also there is a difference (disputed by some, but I believe it) in cat vs. human blood that causes the numbers to potentially read differently on human vs. cat meters. I don't think one needs to buy a cat meter because of it, but I think it is good to know something about it. So basically not all of the glucose molecules, or whatever, actually register on human meters, so the real number can be somewhat higher than what the meter reads.
It certainly can help with hypo fears to realize that a reading of 50 may not mean an actual BG of 50, it may just mean that is what your meter reads. That's why it's a great idea to test a civie like you did. I have heard of civies testing in the 40s, so that certainly makes those numbers less scary. If you are thinking that normal starts at 70 I can see why you might be afraid of shooting a little bit more insulin!
It is frustrating though b/c you never really know what number is a "real" number and what isn't. But you can still figure out the general trend - numbers are good, or numbers are high - and base decisions on that.
All in all the whole thing is kind of a weird and wacky topic IMO. The idea that something like 40 could actually be in and of itself a good number

, and the idea that the meter manufacturers don't show you the true reading :roll: b/c they think we are too dumb to handle it. So it's all kind of shrouded in mystery. There are a number of threads on it in Think Tank and other places, and various articles comparing meters or whatever, but from what I've seen everyone has their own opinion and there's not really a lot of hard data in any direction.