Skilled labor, such as master electricians or certified mechanics, are generally well paid, often have a decent amount of independent thought in their work, and are generally hard to replace (and therefore hard to outsource or layoff). They are also unlikely to be automated any time soon, though it is possible.
On the other hand, unskilled labor tends to be easy replace and is much more likely to be automated in the future. For precisely those reasons it often comes with low pay.
Just as my personal perspective, I could easily support with pride, my (currently quite young son) if he decided he loved cars and wanted to become a mechanic, for instance, but I would want him to consider very carefully before seeing something like being a janitor or factory laborer as anything more than a way to pay his way through college.