The space shuttle Discovery was grounded recently--not by technical difficulties or lack of government funding, but by woodpeckers. Yellow-shafted flicker woodpeckers found the insulating foam on the shuttle's external fuel tank irresistible material for pecking.

The foam is critical to the shuttle's performance. Without it, ice forms on the tank when it's filled with the super-cold fuel, ice that can break free during liftoff and damage the giant spacecraft. The shuttle was grounded until the damage was repaired.

Marriages are frequently damaged not by big things--infidelity or abuse or abandonment--but by the little things. Criticism, lack of respect, and taking each other for granted peck away at the relationship and keep us from reaching the heights.