Their home decor felt lifeless; it was so vanilla.
The term "vanilla" as a reference to being plain or boring dates back to the 1970s, stemming from the historical association with vanilla bean ice cream. Known as the most "universal" or "boring" flavor, vanilla bean ice cream led to the use of "vanilla" to describe anything considered standard, unexciting, or conventional. Most social media platforms frequently use the phrase in a neutral or slightly negative context. For example, one might describe a newly hired employee as "so vanilla" if they seem to lack distinctiveness or individuality in their personality.