One of the things that made me interested in fonts was many years ago when I looked up the difference between Arial and Helvetica, and ever since I did that I react every time I see Arial used in print or signage because some of the letters are really awful in comparison. The most obvious difference is probably the capital R which to me looks terrible in Arial.
Here's an image showing some overlay examples: https://i.imgur.com/1sdXiNY.jpeg