For months I’ve been swearing at the email client I have to use at work because in the Mac version, the user has no control over the font used to display the messages. You can specify this on outgoing messages, but not on the ones you read. The manual says this is because the font size is hard-coded into the client—only in the Mac version.
So after five months of squinting at my email, this morning I discovered that making the whole window wider increases the font size in the message display.
Whoever designed this interface needs to be dragged into the street and shot.