A relatively small error or failure in a computer device or system that triggers off an undesired result.

Common program design errors: inappropriate colors for those suffering from color blindness, texts containing type difficult to read due to size or design, cultural implications (for instance, using parts of the body that are shameful or hilarious in a certain culture or symbols associated with cultural or religious identity), etc. Common programming errors: infinite cycle (indefinitely repeated because the condition for ending them is never fulfilled), typographical errors (confusing the digit "0" with the vowel "0", confusing the digit "1" with the letters "I" or "l"...), etc.

Common installation or programming errors: arbitrarily restarting user session for the installation to take effect, supposing that the user is permanently connected to the Internet, etc.