I love fast lenses, particularly 50!
At one point I had four 50mm prime lenses for my Canon system. The very first prime I collected was the Canon 50mm f/1.2 L, then it came a Zeiss Marko Planar T* 2/50, Sigma 50mm f/1.4 Art, and a Zeiss Milvus 1.4/50.
Since the adaptation of the M-System, there are 2 in my small collection for the rangefinder. The Leica Summilux-M 50mm f/1.4 ASPH. is my day-to-day lens, the Zeiss C Sonnar 1.5/50 serves as an alternative.