I was shocked when I was talking with my grandma and she mentioned her mortgage when she bought her house was 18%. This was a couple years ago when I was looking and rates were around 4%. Blew me away.
*Was still sort of true if you had a VERY expensive house.
My parents paid their house off after 7 years, but that is quite a lot easier to do with most of your payment is high interest rates and you have a much smaller principle to attack.