Journal

The world is sorely lacking a sane removable file system. FAT has tons of technical and political problems and yet it remains the only filesystem that is even remotely feasable for cross platform removable disks.

• Small single file size limit (4.2 GB)
• Small total drive capacity
• Microsoft's long filename patents
• Non-free extensions that only work with Microsoft operating systems

If you live completely in Linux, you can format your drives as ext4. But good luck trying to get Windows or Macs to see it.
If you live completely in Apple-land, you can format your drives as HFS+. But good luck trying to get either Windows or Linux to see it.
If you live completely in Windows, you can format your drives as NTFS. Linux does have multiple competing options of supporting NTFS, but they all basically suck (read only, disables journal, etc.)

Case in point:
My car's stereo system has a USB port that you stick a thumb drive into to play mp3s. Guess what the only supported file system is?
New smart TVs have USB ports that you can stick a thumb drive into to play MP4s, MKVs, and AVIs. Guess what the only supported file system is?
My digital camera uses an SD card to store photos and videos that I take. Guess what the only supported file system is?