These seemingly innocuous words may be the central issue in this whole book (or both books to the Corinthians) because this was the sin that led Satan to separate from God's government. He became puffed up about himself. Likewise, the Corinthians were puffed up about how much they knew.
Satan thought so much of himself that he became twisted in his thinking, and he attacked God. We do not attack God directly—this book shows us we attack each other! Therein lies the problem. We attack each other through gossip, rumors, accusations, and things of that nature.
We begin to draw up lists in our minds of the faults of those who have offended us, and we begin to withdraw from them. We will not associate with them. Division begins to occur because they offend us. We say to ourselves, "Well, they were mean to me," or "They aren't intelligent enough," or "They are peculiar," or "They wear garish clothing," or "They have strong opinions about unimportant things."
This is not to say that these things are right and good, or that one should be able to do his own thing at anytime, anywhere, and that others should be tolerant of it. Nevertheless, Satan can, if he is given the opportunity, lead our minds to find reasons to not associate with others—reasons that have nothing to do with sin. Satan is at work.
If the feeling continues unabated, we will eventually come to the place where we will withdraw from fellowship altogether. It will not happen quickly, necessarily, but gradually. Perhaps we stop attending Bible Studies or begin to find reasons not to come to Sabbath services, or we will arrive late to services and leave early. In this way, Satan is slowly but surely moving us toward self-indulgence rather than love.