in one's element

In the state of doing something that one is very comfortable with or proficient in. My mother is in her element in the kitchen and can make just about any dish. Look how effortlessly she skates. You can tell she's in her element.

Fig. in a natural or comfortable situation or environment. Sally is in her element when she's working with algebra or calculus. Bob loves to work with color and texture. When he's painting, he's in his element.

In an environment naturally suited to or associated with one; doing what one enjoys. For example, He's in his element when he's doing woodworking. This term alludes to one's natural abode, as does the antonym, out of one's element (used by Daniel Defoe in Robinson Crusoe, 1719: "When they came to make boards ... they were quite out of their element"). [Late 1500s] Also see in one's glory.

In one’s natural or most comfortable surroundings or occupation; happily situated. The Elizabethans were much concerned with the four elements—earth, water, air, and fire—and regarded these as the proper abode of both living creatures and inanimate objects. By Shakespeare’s time the terms were used figuratively as well, so that he could write, “Down, thou climbing sorrow! Thy element’s below” (King Lear, 1.4). To be out of one’s element, like a fish out of water, was also possible. “He is as much out of his Element, as an Eel in a Sandbag,” wrote Thomas Fuller (Gnomologia, 1732).