Honesty

Engineers are always honest in matters of technology and human relationships. That's why it's a good idea to keep engineers away from customers, romantic interests, and other people who can't handle the truth.

Engineers sometimes bend the truth. They may say things that sound like lies but technically are not because nobody could be expected to believe them.

For instance:

"I won't change anything without asking you first."
"I'll return your hard-to-find cable tomorrow."
"I have to have new equipment to do my job."
"I'm not jealous of your new computer."