'We read and heard many stories about confident and experienced programmers plunging into self-study tutorials, only to give up in frustration after several hours, still wondering, "Where is the application code?" The object paradigm, in which program control is distributed across a set of tightly encapsulated and high-function software objects, was alien to experts in procedural design.

… to use Smalltalk fluently, a programmer must become familiar with a huge class hierarchy and with the tools of a sophisticated interactive programming environment. New programmers often became lost in the hierarchy or spent considerable time in unfocused exploration of the interactive tools.'

"Making Use: scenario-based design of human-computer interactions", 2000, page 103

https://www.google.com/books/edition/Making_Use/s-0ZuadhBBAC...