It depends on which type of trades we consider as eligible for this conversation.
I mean Bucks traded Kareem to LA because he didn't want to be in Milwaukee, but they received a pretty bad return and never won shyt until Giannis. While Kareem won 5 CHAMPIONSHIPS in LA. One of the greatest NBA players of all time and you trade him in his prime for what exactly? Names that nobody remembers.
And then there are hybrid versions of bad trades mixed with bad drafting decisions. Warriors traded their rights to 3rd pcik + Robert Parish to go up to 1st draft pick and select Joe Barry Carroll. He was good in Golden State, but Parish had a superior career and Celtics used that 3rd pick to choose Kevin fukking McHale

one trade that pretty much helped the Celtics build their 80s dynasty. Come on... Parish was also doing well in Golden State
And the worst trade ever is St. Louis Hawks trading rookie Bill Russell to Celtics for a rookie and a win now player. Exactly the same format of what Clippers and OKC did by getting win now players from OKC. And look what's happening now. While St. Louis Hawks won a championship with those guys, you know how many championships did Bill Russell win.