Have been using multi-monitor for about 15 years now. Sometimes it gets a little silly.
At work right now I use an external display as primary, MacBook Pro as secondary screen (spends 99% of its time showing Terminal). I like the main screen facing me straight on. I don't get how people have the bezels of two monitors right in front of them.
At home I use a few different configurations; but the main machine is a Win10 desktop (mostly ASUS hardware).