There are two types of work that occur during the weekend:
The first, which occurs mostly in service industries, is the 'I have to get this done or else I'll get fired' type. This is the most wretched kind of work imaginable; you're putting in the usual soul-grinding routine while people outside are relaxing and enjoying a couple of days off.
The second type, which is immeasurably better, is the 'I'll just pop into the office and finish off a few things' type. It's an ironclad excuse to get away from your family and relatives for a few hours. The office is deserted, so you can get some work done in peace for once. People are also so impressed you're working on a weekend that they don't care how much work you actually got done. And you're generally able to take the time off during the regular workweek, so you can spend a day at the beach while everyone else is suffering at their desks.
For some reason, everyone claims their job belongs in the first category, even if it happens to belong to the second. If, for some reason, your job does belong to the first category, we would strongly recommend doing everything in your power to find alternative employment.