I'm having a lot of thoughts about James Vega and the position he's found himself in. This dude is Commander Shepard's biggest fan. If you looked up fanboy on the extranet there would be pictures of him with his Normandy Forever badge proudly placed on his armor. He doesn't assk WWJD he asks WWSD. He lectures his entire squad about mocking his admiration of Shepard at one point. Then after Fehl Prime, he wages a one man war in a bar full of Batarians badmouthing her when a news story airs about the Alpha relay in incident.
That's where Anderson finds him and gives him the job of a lifetime for him. Commander Shepard's personal guard. Only when he meets them, they aren't Commander anymore. Stripped of rank, grounded, relieved of duty.
He spends six months with them, it's casual although he still insists on calling them Commander, and salutes when he shouldn't, and then the Reapers hit earth.
By the time they meet back up on the Normandy, it IS Commander Shepard he's dealing with. And this is a whole new power dynamic. This is where the myth separates from the real thing. And you can see the struggle as he argues with them about leaving earth only to get a full frontal assault that basically consists of "fall in line LT!"
And again on Mars he tries to "but..." And gets a very firm command that brooks no argument. And he watches them stay with their people, and he's the outsider. That's got to sting after 6 months of being Shepard's one man team.
There's a whole different world between "Shepard" and "Commander Shepard" and he just fell into the deep end. On top of that he's still struggling with some buried resentment over what happened on Fehl Prime feeling like it was all in vain because Shepard defeated the Collectors without the intel he sacrificed friends and loved ones to save.
So he does the only thing he can think of to work it out. He picks a fight with Shepard, a sparring match, he can vent his anger, gauge their thoughts on what he's done, all at once, even if it means getting his ass handed to him. He takes everything they tell him to heart even if he's unhappy about it at least he knows where he stands after.
Maybe the ground feels a little more solid again under his feet. Maybe Commander Shepard isn't exactly the image he built in his head, but he's in a good place to get to know the real thing now. He may not be swimming yet, but he's at least treading water.