Too difficult to see unread messages
It's very difficult due to subtle font differences to see a read vs unread message from another user. Unread messages are simply Bold and read are standard font.
Graham McKendry commented
Lauri Lehman commented
This makes it really hard to see with a quick glance which channels have unread messages. I have to look at the name of each channel carefully to see if they are boldfaced (I am using a dark theme). The settings should have an option to choose a different color for unread messages, for example.