Ah man okay - get ready for me to be actually serious
Now before I start I will first say my interpretation of Deltarune, and Spamton especially is very strange, I mean for fucks sake I think he was green addison but in other more important ways. And I will also say I respect and enjoy other interpretations of this game, I think its very special that anyone can interpret the story because of its vaugeness and thus get whatever they need out of it! Thats also why im especially a fan of different ships in this game! I may be a Spamtenna shipper but that genuinely doesn't mean Spamton x Jevil or Queen x Tenna isn't also cool as hell in my book! And if people be interpreting Spamtenna as toxic, bro thats cool they aren't real you process your feelings with characters the way you need to! As long as the ship isn't literally illegal im not gonna question it lol!
Ah fuck sorry ill actually get to the real shit okay: also we be in xtm trans Spamton territory okay? Okay
While Spamton wasn't wrong for wanting to be a big shot and be happy with his body and fulfilled with his job, his deal with Gaster didn't make him truely happy. He never enjoyed his big shot years to the fullest, always worried it would go away. He finally sees himself in the mirror, but how long will that last? Tenna finds him beautiful, but how long will that last? His identity, his fulfillment, his entire life is in the hands of a corporate entity, so if he gets to comfortable he could slip up and not fulfill what his contract requires.
Because of all of this, Spamton is an incredibly superficial person. He treated everyone as a means to an end in his big shot years, never getting too close. Tenna was the rare person to see the relaxed him, though that was just because they spent time alone outside of work. Everyone else only saw the smiling salesman or the grumpy mailman, and the only other exception was Mike (who i see as a super chill dude that everyone feels comfortable around) and as much as he loved Tenna and knew Tenna loved him back, he just couldn't trust that Tenna would still love him if he wasn't the big shot.
Spamton in game does seem very untrusting of everyone, both saying Kris is his friend and immediately thinking they're trying to tie him down, lashing out so much he almost kills three teenagers. He needs to learn that he can trust others to love him for who he is, meaning he probably didn't even trust the people closest to him until then. And can you blame him? No matter how much Tenna could tell him that he loves Spamton for who he is how could he know?
So how I see it, When Spam starts to get a little old for an Ad, Tenna brings in the contract, it'll make Spamton a citizen of TV Town and he can run for as long as he wants, though the contract would make any old ones mute, removing his connection with Gaster. And Spamton out right rejects this offer. Even if he would be safer under Tenna, even if he could stay in TV Town forever and never have to visit cyber city and see his Addison enemies ever again...he would have to loose his perfect body. He still has the black feathers and white bones underneath he got from Swatch but it isn't good on its own-Tenna will reject him he would hate Spamton if he didn't look like the big shot he fell in love with
But soon Gaster cuts him off on his own, and Spamton's worst fear is thrown upon him before he even got to choose it. He runs away from Tenna out of fear and shame, hiding away in cyber city because it was better than having Tenna see him like that.
But Tenna was none the wiser. We can all agree that even the nicest of his contracts probably aren't the best but either way I imagine at most he just wanted to keep Spamton safe with him forever. And when Spamton runs out the door I doubt he fully grasped the gravity of the moment, going to the phone out of curiosity and assuming Spam would just come back. But then he didn't. Tenna probably waited by the door for days before he could even bear to think about Spamton never coming back.
So when Spamton is finally letting go of his burning resentment of everyone he distrusts, and is shown that people will still love him if he isn't the perfect man, he's reminded of Tenna, and realizes just how much he truly loved him. He misses the hugs he used to avoid from him, yearns for the warmth he used to be sickened by. He wished he could have appreciated Tenna when he was with him, but thats what second chances are for
AND THATS WHY I LIKE SPAMTENNA BOOM IM DONE YAPPING HOLY SHIT
