Idea: keep the private session active, at least until the application is closed. Reason: people often use Spotify to play lullabies for their kids, or they have someone else play music in the car, or they play nature sounds for some pleasant background noise, or they play game music for an evening with friends. We don't want this to distort Spotify's algorithm on what we actually want to hear.
This and similar ideas have been posted again and again and again since 2012, yet Spotify keeps closing them or stating "Not right now". This leaves the impression that Spotify doesn't really want the private sessions to be a thing, which explains why the option is so difficult to find and automatically switches off after a while (which we're not made aware of by the way).
Please, Spotify, we want this, we need this. Don't ignore your paying users. Even if the ideas don't get a lot of votes in a month or so, when you look at the responses over the years (again, since 2012), it's obvious there's plenty of people who are annoyed by the current private session mechanism. This is an opportunity to improve your product!