A black smith works on a horse shoe and has it red hot. He lays it on a metal shelf to cool. A man comes in looking at all of the black smith's creations. He checks them out, picks them up, looks them over and moves from one to another until he gets to the new horse shoe. He picks it up drops it real quickly and shoves his hand in his pocket. The black smith says "Hot isn't it?" The man replies "No, it just does not take me long to look at a horse shoe."
Two things: 1) We do not often take much time for introspection and personal inspection. Communion does not take us long to finish. We might look inside like we are holding a hot horse shoe. Words to songs are sung but not digested. Sermons are heard with the ears but not with the heart. Bible reading is to be done, but not taken personally. 2) If we do see something in ourselves or our actions we might not consider it too long. Looking inside is one thing taking a long look at that which we discover is another.
The man just could not admit he had burned himself. "Unless you repent you will perish."