What does the following quote from Shakespeae mean: The quotation is "Oh what a tangled web we weave when at first we start to deceive."

This line, actually from Walter Scott's "Marmion," displays the domino effect that our lies have on us: One lie generates another, which generates another, and so on. Toddlers are particularly prone to demonstrate the truth in this statement: "Did you brush your teeth, Billy?

"Yes'm, I sure did."

"Why isn't your toothbrush wet, then?"

"Because I used the hair dryer on it afterward."

"Billy, we don't have a hair dryer."

....and so the cycle continues. The "tangled web" metaphor refers to the act of a spider spinning its geometrical home: if it becomes tangled, the points do not intersect as they should, and the web becomes a mangled mess, much like the act of keeping up with one's own dishonesties.