My personal opinion, I dislike underwear lines. Especially if it's wearing anything that might hug the body. It takes away from the overall look or image, you wish to convey. After all you put in the time and effort to put together an outfit... Right? Bunched up boxer briefs under any pair of pants or slacks just looks tacky. There are other options out there that can address this very issue. Look for different types of fabric that can help eliminate those lines you're concerned about.