The first time I bought a Depeche Mode 12" single was when I visited the then-quarterly London Victoria record fair. I bought one second-hand Personal Jesus and one It's Called A Heart 12" for £4 each. I thought that these were the most ideologically 'dancey', and so assumed that they would be the best ones to buy.
As it turned out, I wasn't that keen with either main a-side, the weren't as good as the 4-minute originals, but the b-sides (Dangerous, and in particular, Fly On The Windscreen) were awesome.
Fly On The Windscreen is probably their second best b-side, after the incredible 4-minute instrumental Memphisto - the premier b-side on Enjoy The Silence (1990).