Today I discovered I made my first big mistake in editing the OpenStreetMap: earlier this week I somehow straightened too large a stretch of the Nieuwe Binnenweg in Rotterdam, resulting in a big 'spike' near the Claes de Vrieselaan.

See osm.org/browse/way/51683769/history, version 1.

I couldn't quickly find how to revert to an old version of the situation, so I corrected it manually. I just hope my spike doesn't end up in any not-so-often updated copy of planet.osm....