The “golden rule” in a situation like yours is to “judge everyone favorably” (Ethics of the Fathers 1:6). Here’s a story from the Talmud to ponder:
A man went down from the Upper Galilee and was hired as a worker for a landowner in the south for three years.
On the day before Yom Kippur the worker came to his boss and said, Give me my wages so I can support my wife and children. He replied, I do not have them.
He said to him, Give me produce. He replied, I have none. He said to him, Give me land. I have none. Give me animals. I have none. Give me pillows and covers. I have none.
The worker slung his things over his shoulder and went home frustrated.
After the festivals the employer took the worker’s wages in hand, and along with them loaded three donkeys - one full of food, one with drink, and another with tasty foods - and went to his worker’s house.
After they ate and drank he gave the worker his wages.
He said to him, When you asked me for your wages and I told you I have no money what did you suspect me of? I said perhaps you came across inexpensive merchandise and bought it.
And when you said to me to give you animals and I replied that I have none, what did you suspect me of? I said perhaps they were hired out.
And when you said to me to give you land and I told you I had none, what did you suspect? I said perhaps it was leased out to others.
And when I told you that I had no produce what did you suspect? I said perhaps it was not tithed.
And when I told you that I had no pillows or blankets what did you suspect? I said perhaps he donated all of his property to Heaven.
He said, I swear that is what happened. I vowed off all of my property because of my son Hyrkanus who did not go to learn Torah. When I went to my friends in the south they annulled all of my vows. As for you, the same way you judged me favorably the Omnipresent should judge you favorably.
This approach to judging others favorably is codified in Jewish law by Maimonides as follows in his commentary on the teaching in Ethics of our Fathers:
If someone is unknown to you and you do not know whether he is a righteous man or an evil one, if he does an act or says something that could be interpreted as either positive or negative, judge him favorably and do not think of him as having done wrong.
If one was well known as a righteous man with good deeds, even if you see him do an action whose every aspect seems to be bad, and the only way of considering it good is through really stretching things and assuming a very remote possibility, it is still obligatory to interpret it as good based on that possibility.
Coming back to your case of the “non-meeting” with your friend, the Jewish ethical and legal approach would be to give your friend the benefit of the doubt and think that your friend was incommunicado due to some emergency.
Just remind yourself of that man from the Upper Galilee if you find yourself still upset. Need I say more?
