What are your worst farming experiences?

Regarding getting weapons or frames. In my case I'm Legendary2 and trying to get everything in game. So far I can't handle Cinta from duviri. Been doing it for months. Brakk BP hasn't dropped for 6 years. Aeolak, Hespar and mandonels are too boring. Voruna had really low rates for me. Sporothrix was too long omg.