The biggest problem so far from week 3 is that it is very easy to lose count after 20 or so push-ups. I just did set two of day 3, and I'm noty sure if I just did 22 (as per the guide) or 27. I count in multiple of five to try and make it sound easier. Ie 20 is just four sets of 5. But if you lose count you think "Hmm, mayde should do a couple more just in case".
Set three here I go...