So at work we have this nice flexible photocopier/printer/scanner/even fax machine (I think) that just works. Send it jobs over the network of your choice, and printout soon appears. A3 or A4, all is happy.
Only today someone sent a job on US Letter just ahead of of mine. I tried to figure out how to get the printer to print it on A4. It's not obvious. I fed a sheet into the manual load and said "It's letter, honest", to which the printer replied "The guides aren't in the right place for letter. Please move them".
Gah! It's smarter than me. Failing also to find a way in the UI to say "put this job on hold", the only way I could find to get my printout out was to cancel the offending job. Grr.
At least it's not the Sun compiler documentation from around the time of Solaris 2.3 that came as a Postscript file. Formatted for US Letter, obviously. If you sent it to the printer and expected it to "jam" (until you pressed shift continue - being an HP Laserjet the UI was small and comprehensible), instead what you got was a neat printout on A4 saying roughly "you don't have US Letter in this printer. Please load the printer with US Letter paper and try again"
Fortunately I don't think that those culpable work for Sun any longer.