Actually I feel I am prety lucky about the relationship between my yamily and me being a dev. My dad is a developer as well (in fact, he was the one who taught me most of what I know today; not as in general coding, but good and bad programming practices, tips what to do next ...) and my mom just started learning Python.
So they know prety well what it means to be a dev and have quite realistic image of what to expect.
To be fair, I am still the one who usualy fixes broken printers and replugs unplugged ethernet cables. but that is because I enjoy doing that. I take it as a challenge for myself to figure out what/how/when went something wrong. Most of the times I try to figure that even without touching the broken things.
Anyway, getting off topic.
Alltogether I don't think that they have too unrealistic expectations, but if I had to chose one, it'd be my learning capabilities. I can't learn complete java in 2 days ...