I agree that code with too small functions can be hard to understand, especially if the naming of functions is not top notch. And naming things is one of the hardest parts of programming. Ability to give good names requires thorough understanding of concepts involved, which often isn't true the first time (or even second time) you write the code.
There's also interesting discussion about "optimal" function length in Steve McConnell's Code Complete. If I recall correctly, there was no evidence that functions of even 100 LoCs for complex algorithms were significantly more error prone than similar code with shorter functions, and that very short functions actually lead to more bugs than code with functions with reasonable length. I think it is because of naming: it's hard to name hundreds of small things well.
There's also interesting discussion about "optimal" function length in Steve McConnell's Code Complete. If I recall correctly, there was no evidence that functions of even 100 LoCs for complex algorithms were significantly more error prone than similar code with shorter functions, and that very short functions actually lead to more bugs than code with functions with reasonable length. I think it is because of naming: it's hard to name hundreds of small things well.