GIFs Photos Icons Clip Art Murphy's Laws 1. If anything can go wrong, it will.
Nothing is ever as simple as it seems.
Everything takes longer than you expect. If there is a possibility of several things going wrong, the one that will do the most damage will go wrong first. Left to themselves, all things go from bad to worse. If you play with something long enough, you will surely break it. If everything seems to be going well, you have obviously overlooked something.