What are some unexpected things about working as a SWE different companies?

Banks - no prediction markets or even day trading, and depending on your role you may need to take the SIE or even get all investments manually approved

Defense contractors - no using your phone at work or looking up answers on Google/StackOverflow/AI... hope you like reading books!

Amazon - no slideshows (multi-page documentation packets are used instead)

The Home Depot - you have to work customer service at a retail Home Depot location at least once a year

DoorDash - you have to work as a delivery driver at least once a year

Epic Systems - you have to go to "church"

Jane Street - entire company uses a niche programming language called OCaml, and they're so worried about non-competes that they pay you for 1-2 years to do nothing to help your insider knowledge expire