Gamer1234556
Farmhand
I always found it very interesting how the game really tries so hard to draw the fine line when it comes to addictive substances. Like, alcohol is a huge theme in the game, but it's depiction of it feels so... muddled, if that makes any sense. Like on one hand Shane and Pam have genuine problems with alcohol, but on the other hand, the Saloon is a massive hub where you farm friendship points, and Wine is so lucrative that most players just end up in the trade anyways.Like many things in SDV, how much Sebastian smokes something else than tobacco, is left to the player's own interpretation. So for his 10-heart event, it could totally be a regular cigarette. Moreover, this event shows Sebastian considering to quit smoking, because two people that he cares about (his mom and the farmer) are worrying about this habit for his health. So, it's interesting to notice that I have an opposite approach to yours regarding this event, that I consider as a positive step in Sebastian's development.
Even Robin's quote about the weird-smelling ashtray she found does not clearly states that Sebastian is smoking illegal substances. It only says that it smelled really weird. And I can name a few perfectly legit cigarette brands that smell really weird also, though the tobacco industry does not put something more illegal in those than the regular hazardous substances they use in all the other cigarettes.
(My own interpretation of this quote is still that Sebastian smokes marijuana, but other ways are open).
I think that Stardew Valley characters are really well tailored because they have enough depth to lead to players discussion like this one, though they have enough grey zones in their story to let players fill the gaps with their own imagination in an engaging way. That's really a strength of the game.
It's also implied that Poppies in this game are a hated gift because of the war going on, but at the same time the game states that they are used for medicinal purposes. Cigarettes and Tobacco products exist but aren't an ingame item. I think ConcernedApe was worried that he would end up turning the game into a drug dealing simulator, and that is why he didn't go with that. I don't have any proof he ever once thought of it that way, but it wouldn't be surprise me if he thought about it at least once.