For me it’s Birds Of Prey. The dialogues are bad, the premise is uninteresting. I watched it and I don’t remember anything from it. My memories of that movie come from the trailers and stills around the web.
I can't pick. I'll say Suicide Squad 2016 as well - it's not a Suicide Squad story, the costumes and face tats all look terrible, and half of those characters can just be removed without any influence on the plot.
