I feel like Keita (Nate) having self esteem issues isnt talked about enough, so I'll make a post about it. Its probably gonna be messy, most of this is just gonna be a personal interpretation (from someone with huuuuge self esteem issues). Its mostly gonna be based on anime timeline material because for some reason, my mind just forgot about most game stuff, please forgive me. Also, manga isn't mentionned, I didn't finish it yet...
Also, please forgive me if my english kinda suck, as u can guess its not my native language and im tired and so losing my grammar.
So, now, lets get into the main topic.
To me its painfully obvious he has some kind of self esteem issues (or wtv u call it). Like, everyone is calling him "average", "plain" and all and, obviously, that will have consequences on him. He's at a time where little comments like that can have a big impact on him. Also, hes like the only kid that doesnt stand out amongst his classmates etc. He probably must feel so untalented and forgettable and that hurt as hell. And its not something you only think about it once, no, its something thats constantly somewhere in your mind, and that you think about everytime you see someone being good at something, standing out for that etc. For such a young kid (cuz hes 11), that must hurt as hell. Yokais are probably the only thing that makes him feel special.
I feel like its mostly in anime, he only get called average a few times in the games, and he get mad when someone say that (as he should) and hes probably hurt too.
Now, to explain my point further, I'll use the official guide/books.
He literally describe (cuz yes, i think this opinion is from Keita POV) that there's nothing worse than being "average" and for him, being average means he's "boring". Except that, in anime, he get called average almost every ep. He literally fears that his friends will think of him as boring, and probably fears he'll leave him if he is, and that fear get intensified since his friends call him average. Having your friends always call you "average", something you see as "being boring" will obviously makes you feel like you have less worth/feel bad about yourself, he may have thought smth like "Am I really this boring for them to always say it?". It may not be alot, but for such a young kid, always hearing that WILL create insecurities.
Before Yo-Kai, his biggest priority is literally "fitting in". Its literally mentionned 4 times. Because when you don't fit in, you're often called a "weirdo", and that creates a distance between you and other people, and isolate you, which, yes, you guessed it, usually makes you feel sad/depressed. And usually, when you're like that, you're not really going to feel positive about yourself... you can think that theres something wrong with you and that's why you don't have friends, which creates more insecurities and a lack of self esteem. Also, his other priorities, "impressing his friends" and "showing katie he isn't just average" kinda goes in pair. Since average = boring, he want to show his friends he isnt boring, that there's something nice, cool about him. That's something no kid should think about, honestly... he's a wonderful kid. Wanting to impress others is something you may do when you have self esteem issues, because you want to show others people (and to yourself too) that you have worth.
Even after he got the watch, of of his priorities is still fitting in. Tho now he can see yokai, so its a bit harder...
When you have self esteem issues, you tend to think you're pretty much worthless, and you wonder why people appreciate you, are friends with you, love you etc when you're so useless, forgettable, untalented... The emphasis on "that" is the important part here, cuz it does imply that nate feels hes "unlovable", which is often how people with self esteem issues feels.
Well, that's pretty much all for this post. I hope it wasn't too messy and you guys understood what I meant. To conclude, keita most likely has huge self esteem issues and should see a therapist. I love this little guy so much chat.
Bye bye and have a good day/night!

















