Does everyone (with and without misophonia) agree that sighing mostly invokes negativity?
Unless it's like overcome with true love, or catching breath in excitement, sighing always comes across as negative to everyone.
Therefore it makes sense that for more advanced thinkers, for deep thinkers, for empathic and sensitive people, for folks who are super perceptive - that sighing would invoke a negative reaction.
Personally I find it ruins a calm atmosphere and positive focus / optimistic thoughts.
You could be meditating or taking time to "be bored" unplugged and find creativity, or opening your thoughts and focus to options and ideas - then it's shattered by some sighing sound , causing you to feel the fatigue, anger, or that you have to do something.
Fecking hate the sound of it, that I make sure to not do it myself. Takes effort, especially as I'm 39 and get sore etc , but I refuse to sigh audibly , and instead take time to breathe or slow my heart rate down or take an extra few seconds after doing something sudden. If angry and get up and walk away or go be alone... No one hears my noises. It's called common courtesy.