David Platt in his book, Radical, writes this statement: "Part of our sinful nature instinctively chooses to see what we want to see and to ignore what we want to ignore."
We can own up to the "typical" sins that are so commonly shared (lust & pride as men) without letting the Holy Spirit actually reveal to us the true nature of all the sin that has a grip on us. It's in ignoring those "other" sins that we are only fooling ourselves.
We miss how talking about other people is gossip as we think it is "Christian concern." Complaints about methodology and structure in the church are "voices of reason" instead of recognizing them as dissension and divisiveness. Talking suggestively in person (or online) with someone of the opposite sex is seen as harmless flirting when it is adultery and harmful to both people and their families. Crude jokes and comments made between friends is painted as simply having fun when it is destroying a level of purity within our hearts. Having a few drinks too many is "not that big a deal" when God specifically tells us not to overindulge in any area of our life. A small lie that is told to cover over a small trangression isn't a big deal since nobody is really hurt even if God's Word tells us to let "your yes be yes and your no be no."
Hiding this sin from other people seems second nature since we don't want others to know what we struggle with, but the true danger comes when we hide it from ourselves. Honestly, I believe that we hide them because we are afraid it is too hard to let God work on them. The process of the Holy Spirit making us aware of this is not without pain, but it is necessary for us to be holy as God is holy.
We can only truly be free when we ask God to reveal all of the sin that has a stranglehold on us-those that we see and even those we try not to notice.