Lying is an essential part of the human condition. That's why we have evolved with the ability to do so. Within limits, it is healthy and natural and makes the human world go round.

You are living with alzheimer's disease in a medical facility and ask me why your husband has not shown up yet. Your husband is deceased but you have no capacity to remember that because neurological disease has destroyed your hippocampus.
"He probably got stuck in traffic. You know how it gets for him on that commute after work. I'll let you know when he shows up" (you ask me the same Q in 5 minutes and don't remember having asked the first time)

You are my friend and love your new haircut but I think it's far from flattering and you ask what I think.
"You look lovely!"

You are my girlfriend. I just met your mother for the first time. She was bizarre and did not present with good boundaries. You are close to your mother and ask what I thought of her.
"She was lovely. I'm glad I got to meet her." (boundary issues will be addressed later on a case by case basis without a direct assessment of mama bear's character)

You are my date and want to go on another date with me but I never want to see you again....I was terribly bored the whole time.
"I enjoyed meeting you but I don't see this developing. Best wishes to you."

You are driving me home in your Uber vehicle and ask if I am single.
"Nope. My husband is waiting for me. He's a cop."

You are my abusive partner and ask where I was when I came home late after a doctor appointment where I asked about women's shelters.
"I had to return a cracked glass to the store, those ones we bought the other day"

You don't respect boundaries and want my money.
"I don't have any money on me."

You are the daughter of a terminally ill mother who recently died. As medical POA, you made medical decisions which caused your mother more suffering because you could not let go of her. You were psychologically unable to put your dying mother's needs before your own. You ask me if I think you made the wrong choices prior to her death.
"You did the very best you could. You loved her. You supported her. You have nothing to feel badly about."

You are my friend living with PTSD and just told me you threw a drink in your bf's face after you saw him kissing another woman. You ask if I think that was a terrible thing to do.
"I think you were shocked love. And you responded in the moment out of shock. Maybe you'd like to chat with a therapist?"

You are my friend. You cooked dinner for me. It was bad. You ask me how it was.
"It was delicious. Thank you very much."

You just started dating a guy and think he's wonderful but I think he's obnoxious though your life is not in jeopardy.
"I enjoyed meeting him. Thanks for setting this up!"

You are my partner and I love you. You ask if I think you have gained some weight.
"I didn't notice love. I think you look great."

I could go on Lying can save us, save others, and maintain peace and harmony in our corner of the world. Some lying is obviously unhealthy and not okay but I doubt that I need to specify those examples.