Why?

Why do "tug" boats push their barges?
Why do we drive on parkways and park on driveways?
Why do we have hot water heaters?
Why do we play in recitals and recite in plays?
Why do we put suits in a garment bag and garments in a suitcase?
Why do we sing "Take me out to the ball game," when we are already there?
Why do we wash bath towels? Aren't we clean when we use them?
Why does "slow down" and "slow up" mean the same thing?
Why does an alarm clock "go off" when it begins ringing?
Why does flammable and inflammable mean the same thing?
Why doesn't "onomatopoeia" sound like what it is?
Why don't you ever hear about gruntled employees?
Why don't you ever see baby pigeons?
Why is a person who plays the piano called a pianist, but a person who drives a race car not called a racist?
Why is a women's prison called a penal colony?
Why is it called a "building" when it is already built?