I'm in a role that involves a lot of communication as well as code. I often get my best development work done on Friday afternoons because everyone's already spent the rest of the week asking me questions/updating me on things and they're out of things to say and/or goofing off in anticipation of the weekend.

That said, on Fridays I like to:

- make sure I've listed out all the things I need to talk to people about next week

- get to inbox zero

- clean up my personal to-do list

- update my calendar to make sure I've blocked off time for development work next week

- push all local work to the remote repository

- take notes on next steps/blockers for my current project/task

For an individual contributor, the last one is the most important. The weekend is the most massive context switch you can have short of a vacation, and it'll take you much longer to get back in the zone if you have to re-excavate the various layers of things you need to do in order to do the things that will let you do the things to fix the bug/implement the feature.

Pro tip: do the same before you go home every night, too, and save yourself a headache in the morning.

Leave work early and have a weekend. No better way to have a productive Monday

One thing you don't do is release changes to production in a hurry on Friday afternoon. Often that leads to working through the weekend thus not being refreshed on Monday.