So we've tackled the first two commandments and now we're on the 3rd and 4th...
3. Thou shalt not take the name of the Lord thy God in vain.
4. Remember to keep the Sabbath holy.
First of all, the third commandment is mostly literal. As in, when you say: "Oh, my god" or "Jesus Christ". It may apply when you use God's name as a curse word. Another way to use God's name in vain is to claim that He wants us to do certain things (bad things that is). Just think of yourself, if somebody used your name as a curse word, wouldn't you go all berserk? :)
To be honest, I'm not sure if everyone has broken this commandment, since if you don't know God, you can't use His name in vain, wouldn't you? Those that have never been exposed to western culture would probably be able to relate to what I am saying... :D
The next commandment is to keep the Sabbath holy. When the Bible says this, It means that we should reserve a day to not work and worship Him in that day (Though It doesn't mean that this day is the only time to worship Him). The Sabbath has been always connected to the 7th day which is Sunday, but there is no specification that it has to be Sunday, so long as we have one day in which we worship Him and not work and I'm sure everyone of us has broken this commandment... :), please share your thoughts in the comment section.
So that's that, these two commandments aren't really the most common two be broken but they are equally important as the rest of them, next time I'll be discussing the next two commandments... :D