The problem arises when the internet is wrong. For instance, just yesterday I was setting up Postgres* (something I haven't done before) and ran into an error about peer authentication when trying to run psql as root. If you google this, pretty much all the results tell you to set the authentication type to 'trust' for the postgres account, which effectively disables any kind of checking for local access to an account with superuser permissions to the database, creating a privileged escalation vulnerability. It took me about half an hour to find out about user name mapping and get it to work.
And as someone pointed out the other day, this is especially rampant with certain languages. e.g. PHP.
Googling a problem is certainly an important step for getting ideas, but sometimes it's worthwhile reading the docs and figuring it out from first principles, because quite often understanding and checking the code can take as long as writing it.