[And Suga is very good at spotting lies. A big part of his job is knowing when to believe people and when to point out that they might perhaps want to consider not saying things that are full of crap.]

Yamaguchi-kun, if you don't like him, why didn't you ask for help to deal with him? You know we're not weak, we could always help you deal to him. [He says it light and friendly, but Yamaguchi's been with the family long enough to know that Suga dealing to people tends towards permanent solutions.]