For example, extracting the phonemes from a raw audio stream or detecting the edges of an object. Things that seem trivial to humans are actually quite complex. In fact, how difficult they really were was probably not fully understood until AI researchers began to investigate the complexity of getting computers to solve them.
Consider, for example, isolating phonemes from raw audio data or discerning object boundaries. Such tasks that seem straightforward to humans are actually quite complex. It is only now, with AI research, that we fully comprehend how difficult these challenges really are.