I work as a desktop support tech, so people don't really overestimate my technical skills when they come to me expecting me to fix things for them. What they do overestimate is the level of knowledge it invariably takes to fix their problems - people tend to be shocked when they ask "How did you even know to do any of that?" and you tell them that you didn't have any idea of how to fix their problem until you sat down to look at it.
For instance, around our support area I'm apparently something of a resident expert at removing malware (or so I'm told whenever they send me out to places I don't ordinarily respond to because the local tech is stumped). If the user whose computer I'm cleaning is present while I poke and prod and then surgically remove their infection, the topic of how I learned to do the seemingly arcane feats of technowizardry they are watching me perform tends to come up, and I always tell them that there was never a delineating point where I suddenly learned any ancient mystical secrets, I've just been sitting down and experimenting with and reading about the underpinnings of their OS for years. Consequently I'm familiar with how the system itself works, so I know roughly where to look when I need to figure out how any given piece of malicious software is launching, and all the previous infections I've had to purge mean that I'm rarely if ever surprised by how that particular infection insinuated itself into their system.
From my perspective, nothing I'm doing is particularly arcane or reliant on specialized knowledge, but I've spent essentially 20+ years now interacting with computers in ways that your average end user - who just wants to sit down, launch their programs that they need to run, and have it all work - hasn't. I tinker, experiment, improve - things like keeping your software up to date and instituting proper security measures are second nature to someone of my mindset, but users, unless its been driven into their heads that they have to, would probably never even try to do that, let alone consider why they should. Expecting what I consider basic computer maintenance from an end user would be a lot like asking them to "overclock their toaster-ovens" - they have no idea what that would do, how to do it, and even if they had a rough idea they wouldn't try because they'd be worried that it would just end up breaking.