This is my biggest irk about Sorbet: because its signatures are wordy and because it can't infer the generic type of a private method, it slightly pushes you towards NOT extracting helper methods if they are going to be 2-5 lines. With Sorbet annotation, it'd easily become 10 lines. So it pushes towards bigger methods, and those are not always readable.

If only private methods would be allowed not having typing at all (with a promise of not being used in subclasses, for example), and Sorbet would be used mostly on the public surface of classes, it'd be much more tolerable for me.