Pretty much any time he was whining like a bitch about his problems but yet never getting them fixed or sought out. Gee, those townie episodes sure could have filled a void somewhere in a perfect world
I'm pretty much saying any time we were developing the pink diamond plotline through his perspective, but now with the hindsight that we're suppose to be seeing Steven becoming worse and worse off from these events, it really makes his later appearances all the more fucked up to rewatch.
Showing that he's apparently 'suffering'.
The earlier Steven (who wasn't totally useless, hence why I honestly rank S1 lower than S2-S3) had so much optimism about him that isn't yet corrupted by more developments about who Pink/Rose really were.
Anything beyond the original show dead ass is a parody of himself.
The Movie is him ACTUALLY reclaiming what he lost during the timespan of CYM and The Movie, it was a sad drop that he had to regress so far to actually make sense of why he's not kicking Spinel's ass to begin with beyond the rejuvenator's bullshit.
He became so unlikable in SU:F, his problems that he never saw help from just boiled over into a toxic mindset intentionally, and he was just back to almost his S1 self of seeking answers but now with the power to be a menace about it.
Pretty sure anyone keeping up with SU:F at the time were wondering who he'd shatter first or when.But they were fucking pussies even with this clearly unhinged Steven and took out the 'trash waifu' who was expendable and EVEN BACK TRACKED ON THAT TOO, yes she needed to come back to not make him completely evil, but that should have happened in the epilogue, not minutes after.
Wew, turned more into a rant about Steven in general.
tl:dr: The more the show progressed it's main plot, the worse Steven became because he was losing what honestly was his best quality.