So what's the problem?
"Being happy is horrible for songwriting, especially for country music. We just want to write about leaving and sadness," Lambert, 27, says in the March issue of Ladies Home Journal. "I have to put myself in a dark place if I want to write something good."
These days writing sad songs is certainly a stretch for Lambert, who became engaged to singer Blake Shelton, 34, in May.
"Blake is outdoorsy, outspoken and really funny," Lambert says. "I used to have no sense of humor. Everything was a big deal. I’ve gotten so much better about not taking things too seriously – and Blake is the reason why."
The couple first met when they were paired on a Nashville duet show. "We were just friends for a long time," she says. "We wrote songs together. He ended up getting divorced and eventually we fell in love."
While Lambert and Shelton plan their spring wedding, they continue to live in separate farmhouses down the road from each other.
"When Blake gets on my nerves, I can go home," Lambert says. "We hang out at one farm or the other, depending on the night. It works for us."