Man that story hits home! I had almost the exact same thing happen with a 2 flute in 6061, I was scared to push it past 35 ipm because the tool was small and I figured I'd snap it, and some guy at a booth just looked at my numbers and said double it and stop being a baby. I thought he was nuts but I tried it and the chatter went away and the chips finally started looking like actual chips instead of dust. Turns out I was rubbing the cutter instead of cutting with it, which is the worst thing you can do to an end mill. That old timer gave you the best free lesson you'll ever get at a trade show. Those guys have cut more metal than I'll ever see and they can hear a bad setup from across the room.

Swap meet guys know everything, no filter needed.

That "sounding too busy" thing hits home for me. I lost a kitchen reface job last spring because I told the lady I could swing by Thursday to look at it, and she says no thanks, the other guy came out that same afternoon. She told me straight up she just liked that he seemed ready to go right then. Hurts because I was actually free that day, I just didn't want to seem desperate so I threw out some made up day. Now I answer with "when works for you" instead of picking a date myself, and I keep samples and a tape in the truck so I can look at stuff on the spot if I'm already nearby. The sad part is the work was fine either way, it was all about who felt more eager on the phone. Lesson learned the hard way.