Lying

I've only been up for 30 minutes and I'm already having a bad day.

First, I nearly stepped on a hairball that the cat coughed up and deposited right outside my bedroom door.

Then I got an email from a friend, someone who had asked me for help with a personal problem, telling me he* has been lying to me. I'm sad because he felt the need to lie to me and I'm sad because he apparently has not been helped by my prayers and efforts on his behalf. (Am I just plain stupid to assume people are telling the truth? I'm so trusting and naive that I just assume people speak the truth when they talk to me. It doesn't even occur to me to question them.)

I know I cannot assume responsibility for the sins of others, but it still makes me sad.

*please remember that in English, the male pronoun can at times refer to persons of either gender.