Glenn's breakdown under his co-workers constant badgering, where he insists that his ridiculous, thankless job is his life, and that he's not a figure of fun. A moment later, Malcolm enlists him for the final showdown with Dan Miller and Nick Hanway: "I need a man—and you're a man". Finally, Butt Monkey Glenn gets some recognition.
Even better is the utterly exasperated and frustrated look Malcolm has while Glenn is still ranting, because Malcolm absolutely knows where Glenn is coming from, there; He, too, is being cut out of the loop and being deprived of his 'ticks' and approvals for new motions. So for once, Malcolm actually sympathises with someone.
Robyn is quite sweet in that scene too, offering Glenn her chocolate and suggesting he goes for a run "because that releases endorphins."
Malcolm gets another huge moment later in the episode. Glenn has run himself ragged keeping Hugh in the loop, and Hugh repays him by ignoring him and favouring Ollie when he finally calls back. Malcolm is the only one who recognises his loyalty, snapping at Ollie:
"At least he's Hugh's Glenn. All you are, mate, is fucking Ben's Glenn."
Which becomes Fridge Brilliance above all else during the fourth series, where Glenn has left for the Opposition. By this point, we know that everything Malcolm does is to keep the party strong, be it trying to jettison Nicola because she's a terrible leader of the Opposition or his leaking machinations, but we know that he values loyalty above all else. And as such, his treatment of Glenn during their only face to face meeting in Series 4 is Malcolm treating him with complete and utter disdain because Glenn made the choice to leave.
Even Mannion comes across as vaguely heartwarming when he refuses to run with the story about the bullying and use it; Certainly, he dresses it up as Do SAC not being worth trashing, but he continues to defend his choice even after he returns to his own offices.
Sam's "Happy Birthday, Malcolm!" anyone?
Yes! Made all the sweeter because he tries to brush her off, but you can tell his heart isn't really in it.
Olly on Glenn's plans to stand in the general election: "I am strangely really proud of you".
It's also very heartwarming to see the usually glum Glenn actually looking quite happy at the prospect. Though of course it doesn't last the episode.
The relationship between Glenn and Olly is generally very heartwarming. It makes Ollie's betrayal of Glenn in season four an even bigger tearjerker. A similar dynamic has emerged between Olly and Nicola, which is affected in the same way by season four.
In Series 3, Malcolm apologizes to Glenn for punching him in the face and gives him a hug. Although, since he's Malcolm Tucker, this might more properly be seen as Nightmare Fuel.
Even more heartwarming (quite possibly in-universe for Malcolm as well) because at first it looks like Sam might possibly be in on the whole sacking thing, since she hangs up on him when he calls her for help contacting the PM. The next scene reveals that she was pretty clearly bullied into it, and looks absolutely devastated as a result.
In the second episode of Series 4, the fact that Sam followed Malcolm into the Opposition. In an otherwise bleakly hilarious episode, it's nice to see that despite not being in power anymore and looking quite subdued, Malcolm still has Sam to rely on.
Malcolm's breakdown in season three and Teri's response.
There's a brief one in 4.04, when Glenn comes to visit Ollie in the hospital. There is the usual snarking between them, but Glenn eventually admits that he does sort of miss Ollie, especially compared to the way he's being treated by the current DoSAC staff, pointing out that "there's no humour in the cruelty anymore."
A rather darkly hilarious, yet oddly touching moment was at the end of the same episode, when Ollie received a congratulatory card and balloon from Malcolm over his role in destroying Nicola's career.
Glenn's attempt at the end of the third season to part with Nicola on good terms. He clearly still resents her for ruining his chances at standing as an MP, and this is particularly clear in season four, but at least he tries, thanking her for their time together. It's made all the more heartbreaking by her disinterest.