This is also true of particular types of "systems". For Example, if payroll operates as expected, nobody pats you on the back. BUT if there is an error (especially if it an error affecting a group or everyone), there is a question of "HOW did this happen?".

There are other jobs that also come into this "genre". For example, a Project Manager is most successful when they are nearly invisible. This is not unique to DBAs, but it is noted that the traditional DBA position has become this type of position. If you perform your job well, your are invisible. If you do not, you are front and center (and often not for long).