I was casting my mind back over BMWs I've owned, and tbh, I don't think there are any that I shouldn't have sold. I've owned many cars that do fall into that category - a low mileage Jensen Interceptor Mk3, for instance - but the BMWs have come and gone at the right time.
Even the M635CSi and the early 840Ci. The turbo M10 E30, the E21 323i (my first BMW), Mrs M's E30 320i, and even the early 80s 5-series Thundersaloon (5.7 SBC, 5-speed manual). They were all great, all the right car at the time, and all sold for a good reason.