So, yeah, it was crowded. People were dropped in on. It happens, even when you try to avoid it. What you do is, you say, “Sorry.” Unless you dropped in so severely that someone was hurt or close to it – then say “sorry” and get out. But under normal circumstances, apologize and don’t make the same mistake again.
Don’t be like this guy:
Surfer#1, paddling back toward the outside and yelling at Surfer#2: “Hey, watch where the fuck you’re going!”
Surfer#3, friend of Surfer#1: “Hey man, at least look at us!”
Surfer#2, still paddling away: (nothing)
Surfer#1: “We can see you, you know. At least acknowledge us!”
Surfer#3: “All you have to do is look at us!”
Fortunately Surfers#1 and #3 ended up more amused than aggro, but in his reluctance to face his mistake and subsequent rush to escape, Surfer#2 ended up trying to paddle to the beach, but washed into the channel, where he wasted time and energy fighting the current, ultimately climbing out on the rocks. What a bummer.