MacGill, who is in the squad for the upcoming Ashes series against England, said "smelling a lot of roses" had helped him regain his Test place.
"Some of my teammates have thought: 'What is he doing? Surely he'd be better off in the gym punching out some bench presses than tasting his third bottle of Chardonnay?'" MacGill told the Seven Network on Sunday.
"I sort of figure, I am only going to be living this lifestyle for a very short period of my life. Cash in ... I'm smelling a lot of roses."
MacGill, 34, credited his relaxed attitude with his return to the Test team after only playing one Test last summer and being overlooked for the side which toured India.
"I'd say it has definitely helped me get back in because my performances have gone through the roof" in Sheffield Shield games, he said. "This has been my best-ever season.
MacGill, who took a New South Wales state record of 54 wickets in the Pura Cup this season, said stress had an impact on sporting performances.
"I watch other sportsmen and I think, 'Just relax, man'," he said.
"They have been thinking way too much about the consequences of losing. Losing is not the worst thing that can happen to you."