The Way He Trolled His Enemies
There was something about the way the Twelfth Doctor confronted his enemies: silent with an element of showmanship. Like when he rolled into The Daleks sanctum in Davros' Dalek casing while drinking tea. Could he have been more of a boss? Because we're pretty sure this was the Dalek's worst nightmare.
His Way of Dealing with Children
The Twelfth Doctor had a way of dealing with children that was a bit like your curmudgeon uncle who didn't really want to explain things to you but did so anyway. (Because deep down he really liked you.) The Doctor dealt with two of Clara's students during his run and both times he treated them like people, not children.
His Inability to Realize His Age
The first thing Clara remarked on was how old The Doctor looked after his regeneration, but the Twelfth Doctor didn't seem to notice. During Doctor Who Season 8, he constantly takes offense whenever people assume that he's Clara's dad, but looking back his desire to throw age out the window is one of the things we miss about him.
His Joy When Things Go Right
Yes, as we stated earlier, the Doctor was not a great hugger, but this one time that he hugged Clara during Doctor Who Season 8 Episode 7, "Kill The Moon," is one of the sweetest moments of his run. While it does feel like The Doctor was playing a cruel mind game in the moments after this scene, the look of joy on his face realizing that Clara could make the right decision fills us up.
His Self-Aware Cynicism
The thing about The Twelfth Doctor is not just that he had an older, wiser, aesthetic, but that he was aware of it while also being unaware of it. The Twelfth Doctor was incredibly cynical but the fact that he called himself out on it made it all the more interesting.
His Socially Awkward Apologies
One of the biggest changes from the Eleventh to the Twelfth Doctor is how socially awkward he is. The Doctor has always been a little out-of-touch with humanity -- he is an alien afterall -- but Twelve had a new level of awkward in social situations, and it was incredibly relatable at times.