Here's a classic mistake that I wouldn't have expected from Google. Can you spot what I'm talking about in this Google Calendar screenshot?
My complaint is with the Repeat checkboxes. Because the labels and the checkboxes are evenly spaced, it's not clear whether a label goes with the preceding checkbox or the following one. Obviously, you can tell by looking at the beginning or the end, or by assuming the convention that checkboxes usually come before their labels.
If you "Zoom in" to expand the font size it gets worse (at least in Chrome):
at a quick glance, it looks like Thursday is checked, but it's actually Friday. (Admittedly, lots of pages don't handle zooming very well.)
As you can see from the second screenshot, you just need to change the spacing slightly to give a clue to the association.
Another solution would be to put the labels above or below the checkboxes. That would make it clear, but it would be non-standard.