ATC formally apologized on comms, even after the airliner crew had a few choice words. They were being vectored by ATC opposite heading, to same altitude we were told to maintain a alt, they were being told expedite climb rate, the controller had erred the performance categories. A Cessna 150. In the Cessna, we were simply VFR in class B with clearance and we saw then avoided an airliner. I gave them unable. It was hazy with reduced vis and cloudy. The airliner did likewise. We all weren't on the same idea page with holding an altitude on a collision path with an airliner. That happened eight years ago. There were many good times with many other professional controllers that saved people. It's the one mistake they make that causes you problems. It's pretty unusual when an airliner crew cussed out ATC and the controller formally apologizes. That SAAB must've had a full truck of JetA and Pax cuz it wasn't doing what ATC wanted as fast as ATC expected. It was trying clawing for sky and it wasn't happening. High humidity, at 95-110F, and full truck of fuel in Memphis was always bad on climb rates. I'm glad I heard that message or I wouldn't be here to type this. So I followed see and avoid. So did the airliner. And the ATC guy apologized then another took his place for the shift. When ATC errs. ATC apologizes. He said later he meant for the SAAB to be 500ft above us.
The comms went dead silent for thirty seconds after the airliner jocks cussed. Then a FedEx flight chimed in "Memphis Center did you have your coffee this morning?" To lighten us all up. Memphis replied getting another cup one of our controllers needs a short break.
I've had controllers vector us around T storms that popped up and were helpful at times.