Some examples of why you cannot blindly follow English grammar rules

If writers write and painters paint and riders ride, then why don’t fingers fing?
If the plural of tooth is teeth and the plural of goose is geese, then shouldn’t the plural of phone booth be phone beeth and the plural of moose be meese? Maybe they should be, but they aren’t.
If the teacher taught, why didn’t the preacher praught?
If a vegetarian eats vegetables, what do you think a humanitarian eats?
How can a house that is burning up finally end in being burned down?
At a bank or loan office, how can you fill in the necessary information as you fill out the forms?
Why is it that when the stars are out they are visible, but when the lights are out they are invisible?
Why do people recite at a play, yet play at a recital?
Why do people park on driveways but drive on parkways?
Answer: I simply don’t know.
[source: http://www.say-it-in-english.com/englishfun.html]