Sometimes USB isn't an option:

The USB interface on my old Samsung Galaxy S2 broke (seems to be a common problem), now the connection just charges, data transfer is borked under Windows and Linux.

So I thought it would be "easy" to use WLAN for that - Samsung itself wants you to use "Kies", proprietary software which works only under Windows. Once I had located the right old version for my apparently-too-old phone, I started to back up my photos. But Kies decides to be super-duper-slow and downloads with 1 kb/s, so it predicts about 48 hours of copying.

Luckily there's sftp on the play store, with that and scp under Fedora it took 5 minutes.

It's like they want you to hate them.