have you ever heard of a lynchpin? They're small and usually extremely important. For example, lynchpins hold the backhoe on to the back of my tractor.

In fact, lynchpins are so small and important that the term is used when there's something that is small but so important that missing it would ruin a project, because the lynchpin ties it all together into a cohesive whole.

Also the replies to my sibling have me confused if i am even awake... who hasn't heard "for want of a nail"?

[dead]