Yep, I think that's a pretty big part of the learning process. Realizing that you had a successful build but some things weren't stable. Naturally this would pose the question: What went wrong? To solve that problem you have to figure out a way to debug the system, make a decision as to how to rectify it, apply a fix, then figure out how to verify.

Now imagine the effort that has to go into making Debian work or what if the issue was related to sporadic kernel crashes. It's a lot of fun if you're into that sort of thing.