Handy Loudness Chart

A common mistake, IMO, is focusing on the integrated LUFS reading while ignoring song dynamics.
 
When I got the new Sgt. Pepper remix, I first gave it several listens, and pronounced it good. Then, I did the next logical thing that a nerd would do and pulled it up in Insight. I was surprised to find it came in at integrated LUFS values around -9. Not up there with modern pop, but pretty hot for classic rock.
 
What saves it from sounding smashed was that they weren't afraid to keep some contrast between song sections, both the short-term and the macro dynamics as a song progressed. Lucy in the Sky with Diamonds, for example, measured -13 on the first verse, while the chorus was -8. Second verse jumped to -10 LUFS.
 
This kind of stair-stepping keeps the energy high from start to end. It counteracts a phenomenon with loudness perception: your ears adjust to a given density, and if a song remains there for several minutes there's nothing to wake them up. But if each verse is slightly louder than the preceding one, while the whole song gradually gets louder, your ears don't become complacent. It feels like the song is going somewhere.