I made these cards based on the now famous British World War poster “Keep Calm and Carry On”, which is in the public domain. You can read about the history here. Rip-offs have become something of a meme. Mail artist and brilliant typographer Keith Bates created the font, based on the original poster series.
The last one ‘please do not ever feed trolls’ may come in handy, when confronted with internet trolls appearing in internet forums. You are free to use it, whenever you feel the need.