According to the book, 'To go berserk' originated from the Berserkers, or wild Norse warriors of great strength and courage, who fought with a frenzied fury known as "the Berserker rage", the Mirror reported.
Next, 'Brownie Points' is a phrase that seems to have originated in the US where a brownie not only stands for a type of chocolate cake, but also stands for a benevolent elf or pixie.
'A bed of roses' was first used by in Christopher Marlowe's 'The Passionate Shepherd to His Love', where the lover promises to "make a beds of roses/and a thousand fragrant posies."
The book claims that the shepherd meant rose petals - and bed of roses would mean a comfortable, easy-to-deal-with situation.
Also, the expression 'The Nitty Gritty' arose in the US in the mid-20th century and it has been suggested that nitty refers to nits and gritty means the grit left at the bottom of a barrel.