Got called to a professor’s office after a complaint his SPARC4 was running slow
Back in 1989 I worked as a one-man-IT-department for a bunch of ex-academic economists doing econometric modelling on a Digital VAX 11/750. This mini-computer was running VMS - a multi-user operating system. All users had admin rights and each one thought that they could make their models run faster by bumping up the process priority as far as it could go - which of course interfered with the realtime processes needed to manage the effective running of the computer. Unsurprisingly, this had the opposite effect to what they intended. When I discovered this was what was happening, I revoked their privileges and after a system restart, sanity was restored. I was thanked for finally making the system work faster.