I got to thinking about this the other day, because trying to main D'vorah right now definitely increases my salinity. I was actually mad about a set the next day, which isn't something that typically happens to me.
But it's nowhere near the saltiest I've ever been. That moment came during Injustice 2. I've been a Harley main since I:GAU, which was the first fighting game I took seriously, and as such I have a deep seated loathing of the Aquaman matchup. Flash forward a few years to I2 and he's finally nerfed to a fair level and...he still 7-3's Harley.
One day I was in a set with some random Aquaman that I felt wasn't as skilled as me, but I wasn't able to overcome the matchup, like usual. Like usual since 2013 and nothing ever changed, but here I was, still banging my head against a solid wall trident rush and from the deep.
Didn't actually get angry, I was all the way past that into outright depression...so I went back to college. Not even kidding, the impetus for me going back to college for a new degree was how awful that mu has been for so long. I'd been considering it for awhile, but that's what made it happen. Still going strong too, I'm a few years out from a chemistry degree.