Good for you, I am not perfect, I have a contract that allows me holiday and to be paid if I am of sick. And if I don't feel great I take the day off, it's a simple as that really. No theft involved, I don't have many a year and probably less if the martyrs did drag themselves in full of germs...
Theft would I presume work both ways. How many people consistently work extra hours and don't get paid for it? A lot of people work jobs where finishing on the dot is not always possible. In my job on most days go over my time by 10 or 15 mins and will not get paid overtime for it.