Lots of people do this because they want to appear reliable, competent or dedicated. But usually it ends up just becoming an expectation of you and people around you.
The day you won't do it anymore you will be criticized (maybe not in your face) for it. And it would become expected of you.
If the workload is consistently overflowing to your weekend that means you are having issues estimating the time/effort it takes to finish your tasks.
It could also mean that your employer is having issues estimating the time/effort it takes to finish your tasks. Or that they aren't, and just don't care.
Overconfidence or people trying to show-off can have you underestimating the time it takes for things to be delivered thus causing these kind of situations.
Also working excess hours tends to screw with estimates as something in the head clicks that you can always work longer if the estimates are off. My estimates are strictly 40 hours/week, no more.
When you’re on your deathbed, you’re not going to wish you spent more time working for your employer.
I watched my father work weekday and weekend throughout his life and never seeming to enjoy a minute of it. I knew that wasn't the life for me.
If I were single I’d be less of a stickler about this, but would still not be ok doing more than 45 on a regular. After 30-40 hours, more working hours rarely translates to more productivity.
Our trick was to work in 90-minute bursts, with 30 minute breaks where we actively stepped away, took a walk, played ping pong or Nintendo, got coffee, stretched, etc.
Unless you're self-employed or at a bootstrapped startup, why give your employer your free time?
And what's not done by Friday, is not done, not my problem really since I'm paid by the hour.
Here's an example: our R&D team needs various national ID documents to train their AI (text recognition). But they hit a wall - where does one obtain 10s or 100s of IDs? Governments aren't handing out specimens. You can't walk up to random people on the street and ask to scan their ID card. Friends and family - too few!
So the only solution is to 'forge' documents... That's what I've been having fun with over the last few weekends!
My employer gets 36 hours a week as per the contract agreed between us. Incidental favours aside, any structural deviation of those hours comes at a significant cost to my family and my personal welfare (e.g., not getting round to odd jobs around the house, domestic chores, hobbies, leisure, sex, and raising a child).
So why are you working in your weekends?
If you enjoy working with distractions and it benefits your work, why not figure out a way to work from home on certain days in the week?
It is not normal to keep on working beyond the agreed upon hours if you are a salaried employee. You're life is simply too short to throw it away like that.
Seems to me that many managers will extract as much work out of you as they can get away with. In some companies you are simply expected to work 70-80 hours a week - not only in programming, but in accounting and law firms too.