Isai has an emotional handicap. He is shy to the point that it hinders him in everything he does not just gaming. If you can go hang out with a group of friends and have a good time, then Isai you are definitely not. There is a lot more to him and his problems than that, but there is no need to really talk about it.
For you though, it could be many things. I often don’t play my best when I play friends or players I don’t know online. And that is because I know how hard it is to push to be competitive in fighting games. And I am lucky enough that I find joy in that. I constantly worry that If I steam roll somebody they wont want to play anymore, and that isn’t good for the community. I will slowly start upping my game as they keep rematching me to push them a little. And I hope at some point they will realize how much fun it actually is to try and be better than the next guy. And I absolutely hate that. Because I am so competitive that I feel it was an absolute waste of my time. But the flip side is that new players sometimes need to be babied a bit. They wont be shit, but at least they will be there when others who do want to be pro come along and need to start somewhere and they don’t get bodied to much by the better players. For the community. But when I play team mates or anybody who says they play or want to be competitive, then I always try win. I never want to lose to somebody who thinks they are on my level. And I never want to stop rematching somebody who is on a higher level.
Maybe that’s how you secretly feel. If not just say it is, because the alternatives are bad.
You could just be bad at games and don’t accept your losses. You could be bad at the game, accept your losses, but are to embarrassed about them so you hold back because then you have a reason why you lost. No Johns. Or the absolute worst. You don’t want to be competitive.
If you want to take it serious you will need training partners who take it serious. Try get in with your local FGC and go to the meet ups. If you aren’t frequently losing to better people then you are playing against the wrong people. Find out when the next closest tournament is going to be and enter. After that you will know if you want to work harder to be better or not. And if you want to be better, you wont want to lose.