"all you have to do is read the methods section in the paper and follow the instructions."
I wish science was that simple. The methods section only contains variables the authors think worth controlling, and in reality you never know, and the authors never know.
Secondly, I wish people say: "I replicated the methods and got a solid negative result" instead of "I can't replicate this experiment". Because most of the time, when you are doing an experiment you never done, you just fuck it up.
Here is an example: we are studying memory using mice. Mice don't remember that well if they are anxious. Here are variables we have to take care of to keep the mice happy, but they are never going to go to the methods section:
Make sure the animal facility haven't cleaned their cages.
But make sure the cage is otherwise relative clean.
Make sure they don't fight each other.
Make sure the (usually false) fire alarm hasn't sound for 24 hours.
Make sure the guy who was installing microscope upstairs has finished producing noise.
Make sure there is no irrelevant people talking/laughing loudly outside the behaviour space.
Make sure the finicky equipment works.
Make sure the animals love you.
The list can go on.
Because if one of this happens, the animals are anxious, then they don't remember, and you got a negative result which have nothing to do with your experiment (although you may not notice this). That's why if your lab just start to do something you haven't done for years, you fail. And replicating other people's experiment is hard.
A positive control would help to make sure your negative result is real, but for some experiments a good positive control can be a luxury.