So Much Energy!
When I Was Your Man," or, "Grenade," if you want some depressing songs about broken-hearts. That said, while Mars may sometimes ply his trade romantic sorrow, his biggest and most popular jams seem to be those with a neigh-relentless enthusiasm for dancing, partying, and other things people like.
You can't go to a wedding, birthday party, or bar mitzvah that features a dance-floor and be surprised when, "Treasure," or, "24K Magic," comes-on, along with other hits. I single-out that duo of jams however because they seem to be the most popular, with their surreal mixture of modernity whilst also sounding like they were dipped into and coated with a healthy dose of 1970's and 1980's nostalgisa--the video for, "Treasure," looks like it was made decades ago in a clear-cut example of weaponized nostalgia (see my posts on weaponized nostalgia for more talk of that).
This energy and sensation of fun is contagious, and the fact that almost any party-situation calls for some Bruno Mars exemplifies this fact. I ain't gonna begrudge him for that.