I don't think that people marry those who are like them, but people who have some things in common, that way they can easily try something new. I also don't think that people marry those who are like them because opposites attract each other. I think this pattern happens so that everyone married to their spouse will have their own ways of trying something their significant other likes.
Korean War, 1950
U2 Crisis, may 1960
Bay of Pigs, 1961
Marshall Plan and Truman Doctrine,1947
Cuban Missile Crisis, 1962
The one that might occur if the animal had a prolonged period of untreated lesion on its brain stem is potential of undetected brain tumor.
It is highly recommended for per owners to immediately do an MRI if you notice a weird bump on your pet's head.