Such a great thread!
For me, this was more 80s/90s, things had started changing by 2000, although I was working for a very corporate American company by then.
I remember:
Smoking in the office. I had a horrible manager with a disgusting yellow stained office who made me responsible for ensuring there was a spare pack of fags in his desk at all times. I forgot one day and he went ballistic. Once smoking was banned in the office, those who smoked would go outside on frequent fag breaks and many of us who didn't smoke would go with them! None of my colleagues smoke now.
Cracking open the wine on a Friday afternoon, or every afternoon in the run up to Christmas. Locking a manager in his office because he was so pissed and out of control.
Mucking about and playing practical jokes on each other when we were supposed to be working.
Lavish Christmas parties with lots of outrageous drunken behaviour and equally lavish staff gifts.
Sending memos through the internal post after photocopying them and highlighting each cc.
Computer print outs on that paper with green lines and holes on the side.
The frustration when the 65 page report you were trying to fax wouldn't go through.
The novelty of email and using it to email friends or send jokes around the office.
Electronic typewriters and booking time on The Word Processor for big reports and saving it on floppy discs.
I think the office I work in now is actually quite laid back by today's standards and we do have a laugh when we can, but nothing like the olden days!