Mmm, yes...but the fact that they're usually flaky means it's that much less of a tragedy when they're flaky to you. ^^; It's a natural thing, like the circle of life...you shouldn't expect the sub numbers to steadily go up, as counter-intuitive as it sounds. It's normal for them to fluctuate.
It's easier for me to be fine with it, because I don't update very often, and I'm always forgetting the number of subs I saw last. At first, I thought I was just imagining that they were going up and down; it took a while before I realized that I was actually losing people occasionally.
But all that means I can just not take them seriously and focus on the numbers of views and likes instead, which rarely take sudden downturns. One of my favorite things to do is root for the next hundred views in the day or two after an update. ^^ (I'm not used to getting view counts with three digits, ok)