What is the biggest difference between Protestants and Catholics?

I'd say the biggest difference is the authority of the Church. Protestants believe in 'Sola Scriptura"- only the Bible is the source of truth. Catholics believe in the Church as well. Amongst protestants, there is a huge variety of ideas, because they all interpret the Bible differently. If Sola Scriptura worked, all the protestants would agree. But by in large, they can't figure out if homosexuality is wrong or not, or whether they should divorce, have women pastors, how much money to give, sacraments, who gets saved, honour Mary..... etc. Protestants are really all over the place! Jehovahs Witnesses even use the same bible, and come to completely different conclusions, like that Jesus was not God, and only 144,000 people go to Heaven. So the bible alone is not only unscrpitural- it has been demonstrated to not work! Whereas in 2000 years, all over the world, the catholic Church has always (officially) taught the same thing. (I say officially because there are always wack jobs who claim to be Catholic, but teach their own opinions instead of truth.)