Life as a goalkeeper is difficult. A keeper can have fantastic game, but if one ball gets past them, they receive all of the blame.
Stats like goals against or save percentage have been used haphazardly to evaluate goalkeepers for years, but they fail to paint the whole picture.
For instance, if a goalkeeper plays behind a good defense they will be expected to allow fewer goals. Conversely, if opposing teams keep hitting top-corner screamers, the keeper allows goals that they can do little to prevent.