A nutrient slurry like Soylent is an act of engineering. It costs $X, has Y nutritional impact, requires Z effort. It is not unpleasant to consume, or shouldn’t be, but that is not its purpose.
That doesn’t mean sensory pleasure is absent from life, it just means it doesn’t come from the slurry. You are drawing a line between nourishment and sensory pleasure.
For fun you add a side dish or dessert. A bit of melon. A piece of chocolate. A small serving of sashimi. Not a lot – this isn’t to fill you up.
It’s a new template for your meal. The main course is neutral and functional. The side dish is interesting and frivolous.