i just imagine that after the series ends, shima would have the hardest time being a spy LOL because most of the spywork he does for mephisto/the illuminati/the order whoever else im forgetting is basically him just tailing yukio wherever the hell he goes and telling all three different details about his activities. imagine what happens after they need him to do something other than tail his oddly endearing boyfailure teacher. think about it 80% of his spywork is just keeping tabs on yukio alone so if he no longer has to do that i bet he'd complain about overwork and then spend every free moment of his time hanging around/running into yukio out of sheer habit. yukio would be like "why do you still follow me around isn't all that stuff over" and shima would earnestly say something like "yea but sometimes i think that the best part of my job was you :/" or "yeah but the job was better when all i had to do was think about you all day :\" and then they both sit in awkward silence bc shima is thinking "why did I think/say it like that. better not elaborate" and yukio in his mind is like "WHAT THE FUCK DOES THAT MEAN HE THINKS OF MEEEEEEEEE??? IM THE BESTTTTTTTT PART???????" and yeah
Yup, i can totally imagine a scene like that















