Mastodon: You click a thumbnail and are flashed with a harsh white checkered box that burns your retina as you watch the deceptive blue progress bar lie to you about how long its going to take. Really it has no idea how long it will be, it just starts fast and slows down every time. Then eventually in another jarring flash, the image you were waiting for finally appears.
Pleroma: The full image has already loaded before the neurons in your brain decided to click on it.
Why Mastodon. Why.