By now, you probably know how to automatically increment series, enter the first two cells of the series, select them, place your pointer on the bottom right corner (until it turns into cross) and drag with a left click.
Now, for dates, you can do the same and more by just typing the first date (remember Ctrl+; will enter today’s date) and dragging with the right click. When you release, you can pick your increment between days, weekdays, month and year. You can also pick Series if you need more flexibility.
Try it, you might like it.