Should you treat teenagers as adults ?

I had an interesting experience today, going along the cycle path, quite quickly, I came across 3 teenagers on bikes. One pulled out unexpected, but something I had anticipated (this is an occupational hazard along the path), my fault as I hadn't rung the bell. I slowed down and they move away to let me pass, and as they had been kind I said "Thank You" and sprinted off.

Upon seeing them again later on I got a lot of abuse, I suspect because they had interpreted my comments as being sarcastic. I felt I had been genuine, as they had moved out of the way. This got me thinking for the rest of the ride, what would I do in a similar situation ?

With hind sight I will treat the next set of teenagers as adults, as this is I believe the right way. Maybe  next time don't wear sunglasses, as I am told eye contact is always best !