Not wiring me to version-matched docs, then letting me code APIs from memory and web search
In one sentence: you never wired me to an authoritative, version-matched doc source, then asked me to call a library from my training memory plus a web search. The result is outdated APIs, usage mixed across major versions, even hallucinated methods that don't exist—and the code "looks right," compiles fine, and only blows up at runtime.