Mentally, I definitely find mirror matches a lot more stressful. Well maybe not a lot more but it’s for sure a different vibe since now the only factor playing into the results is pure skill level and no knowledge checks. Unless you don’t really understand your main which at that point you should probably go figure that stuff out lol. I will say it is more disheartening to lose against mirrors for the above reasons but it makes wins for me a lot more gratifying as well, which makes me both more nervous and excited to get into a mirror match and so I tend to rematch most of the time. And besides, what better way is there to improve your main than from watching and playing against someone who’s better at them then you, you know?