For one thing, words aren't always pronounced the same, nor do they have the same meanings! Try these on for size!
Well, how about the fact that:
...there is no egg in eggplant or ham in hamburger.
...there is no apple or pine in pineapple.
...English muffins weren't invented in England.
...French fries weren't invented in France.
...sweetmeats are candies and not meat.
...sweetbreads are meats, but aren't sweet.
...quicksand can work slowly.
...boxing rings are square.
...a guinea pig is not from Guinea and is not a pig.
...writers write, but fingers don't fing, grocers don't groce, and hammers don't ham.
...the plural of tooth is teeth, but the plural of booth isn't beeth.
...it's one goose and 2 geese, but not one moose and 2 meese.
...you can make amends but not one amend.
...you comb through annals of history but never a single annal.
...teachers have taught, but preachers have never praught.
...we recite at a play and play at a recital.
...we park on driveways and drive on parkways.
...a house can burn up as it burns down.
...we fill in a form by filling it out.
...an alarm clock "goes off" by going on.
...the human race isn't a race at all.
...we wind up a watch to get it started, but when we wind up an essay, we end it.
...a wise man and a wise guy are opposites.
...overlook and oversee are opposites.
...quite a lot and quite a few are the same.
...vegetarians dine on vegetables, but humanitarians do not dine on humans.
...a horseful carriage.
...a strapful gown.
...a sung hero.
...a combobulated, gruntled, ruly, or peccable person.
Have you ever heard someone say "That's the best thing since sliced bread"? Well, what was the best thing before sliced bread?
Why is it called a TV "set" if there's only one?
Why does your nose run and your feet smell?
Why does "cleave" mean both split apart and stick together?
Why is it whether you sit down or sit up, the results are the same?
Why is it called a "building" when it's already built?
Why do they call them "apartments" when they are all stuck together?
How can you "draw a blank"?
Shouldn't there be a shorter word for "monosyllable"?
Why do 'tug' boats push their barges?
Why are stadium seating areas called 'stands' when they're made for sitting?
Why do 'slow down' and 'slow up' mean the same thing?
Why is it when two planes almost collide it's called a 'near miss'. Shouldn't it be called a 'near hit'?
Why are there Interstate Highways in Hawaii?
Why do light switches say on/off? When it's on you can see it's on, when it's off you can't see it to read it.
Why do 'fat chance' and 'slim chance' mean the same thing?
Ever notice that PRICE and WORTH mean about the same thing, but priceless and worthless are opposites?
Why is it when you transport something by car it's called a shipment, and when you transport something by ship it's called cargo?