y'know, sometimes i think about the way suguru acted in jjk0. it's more similar to how satoru acted in high school than to his own high school personality, so i wonder if suguru, to feel closer to satoru and miss him less, along with the feeling that satoru could achieve anything solely because he's gojo satoru, tried to act more like satoru in front of others. also (here's more like a hc) satoru being adored by most that didn't know him that well, being popular with girls and simply the definition of perfection suguru could only ever dream about being, suguru probably thought to himself that being more satoru-like will make things easier for him. cause y'know, he's always felt somewhat expendable, like no one would miss him if he wasn't there, sure, he was strong, but satoru was stronger and strong enough even without suguru. so, naturally, if suguru adopted the all-smiles-and-jokes personality, hid behind a smile very much like satoru did, and buried the humanity hidden in one's vulnerabilities along with his emotions, life would be easier to live.
and satoru would be easier to miss.