Peanuts comic showing Linus sucking his thumb and sitting next to Lucy. Linus says, "Why are you always so anxious to criticize me?" and Lucy replies "I just think I have a knack for seeing other people's faults." Linus turns towards Lucy and throws up his hands, saying "What about your own faults?" Lucy replies "I have a knack for overlooking them..." In your own words, explain the main message of this cartoon.