"Second nature" refers to an intuitive, instinctive, or innate ability, habit, or trait usually achieved because one performs or practices a certain action very often or for a very long time.

Literally, "heavy lifting" refers to the act of picking up and carrying heavy objects.

Wishy-washy , first used in the 1600s, means “lacking in strength, flavor, character, or determination.” “Washy,” literally meaning “over-diluted,” came to mean “feeble, weak, and ineffectual.” Adding “wishy” to “washy” is a use of alliteration for the catchy effect it produces.

The idiom ‘Stir the pot’has its roots in the literal act of stirring a cooking pot to keep the ingredients from sinking to the bottom and sticking.

It means “extremely unwilling to be involved in something and to avoid it.” Historically, people living in rural areas were more likely to encounter wild animals or invading armies and would need to flee quickly to avoid harm. Running for higher ground could also provide protection from floods or other natural disasters.

“To sit well with” means “acceptable” to one’s values or sensibilities. While “not sit well with” shows a feeling of uneasiness with a situation, as if someone is sitting on the edge of an uncomfortable seat.

Butt out means “to cease interference or involvement.”

Quantum leap refers to “a significant improvement or crucial development in something.”