Blue head canon that is 100% me projecting:
Blue sometimes gets so viscerally angry that he gets close to passing out. Like; head spinning, nausea, vision fuzzing. He can normally keep people from noticing by storming off or just making himself look as big and angry as possible with a 'barely internal' scream and people will take the sudden quiet the light-headedness causes as him keeping himself from saying something he'll regret.
It got so bad that he actually made the person he was angry at (probably Shadow) very concerned because he actually looked all dizzy and had to sit down to keep from passing out.
Also if he's angry for long enough, particularly active and angry, he ends up spending the rest of the day or week- depending on how long he was angry and active for -really drained both emotionally and physically.
This is deeply concerning to the people who know about it. Which isn't many lol.
I like to think that after the events of the manga he did start to mellow out a bit, which was helped by the week long exhaustion that came with spending the entire journey with a lit fuse. Blowing up at everyone for every reason is bad for his health.