Nobody knows this but my beagle and I, but I have a secret. I can sing. I can sing really, really well. The catch is, I can only sing well to a Frank Sinatra record. Sinatra has that effect on you - his phrasing is not only impeccably tasteful, it is also instructive. By the time you have listened to a Frank Sinatra album the fifth time through, you've learned how to put just the right inflection here, and drop a half-octave here, and - you get the idea.
Frank Sinatra still has one up on me, and you, and everyone else - he didn't have to listen to a record of himself to know how to sing a song like Frank Sinatra, and for a time, if it was on a Sinatra album, you knew damn well it was a great song receiving its definitive treatment.
In private, Sinatra was often a jerk. That's unfortunate, but it doesn't diminish his accomplishments in the studio and on stage. If your image of Sinatra is an old man belting out 'My Way' at the top of his lungs, pick up a copy of Sinatra at the Sands from 1966, or better yet, listen to the subtlety of the singing and the melodies on the incomparable 1954 album In the Wee Small Hours. Fifty-one years later, it remains the quintessential heartbreak album. I can think of no other work in any medium that better captures the despair and longing of the lonely. If you're looking for upbeat, you can't go wrong with 1955's Songs for Swinging Lovers.
Sinatra was doing concept albums before most artists even considered the long-playing record a different medium from singles. The 'concept', at least in what most would consider the 'classic Sinatra' era of the mid-50s and early-60s, was a sustained mood rather than the telling of a narrative. When it worked, most spectacularly with the Nelson Riddle Orchestra, it was timeless.
I like my Grateful Dead, my U2, my Rolling Stones, that's a fact; at his peak, though, Sinatra inhabited a song in a way that Bono, Jerry, and Mick can only look at in envy. I've been going to Las Vegas almost yearly since the late '70s; how I wish I had taken the time to go see Ol' Blue Eyes just once. I'm certain that even an old, diminished Sinatra was still the best show in town.