I'm a huge fan of games with a good sense of humour but adding a good amount of serious moments, memorable and likable characters and making it feel like you yourself are living in the game making it more personal. Undertale is right up there with Earthbound and Persona 4 as one of my favourite RPGs ever and I think everyone should at least try it once. One last thing, the soundtrack is fantastic so give it a listen if you get the chance.