Is it me or did GPT get noticeably more natural in word choice recently? You can see it between 4.1 and 5.5 here, but I'm not sure when that happened. (My guess would be one of the recent 5.x releases.)

Thanks from where I'm looking Grok 4.3 and Claude 4.7 do a better job on the informal close friend/coworker vibe.

ChatGPT sounds fake / formal phrasing (for the specific close friend context) and has em-dashes and uses capitalization. Hence, ChatGPT does not, imo grok the assignment ;)