I got back from our dives yesterday, they went really well. I can see 3 being the ideal number with good divers, as it gives you 4 hands instead of 2 if something goes wrong and, well, it's fun being with two friends underwater.
My buddies, however, were somewhat incompetent, one especially. He kept shooting ahead and my other friend would follow. This situation sucked because we were in an area very rich in animal-life, but we missed it all because of that. Where was he going? Why was he going so fast? I don't know. He's somewhat clueless to begin with, and his diving is an extension of that. As my friend was following him, I had no choice but to follow or be left behind. Neither of them were at all checking behind to see where the other(s) was(were). We got down to 60ft (we're only OW with 12 and 15 dives apiece) and He finally looks back. My tank is at 1000psi, I signal up, gesturing we level off at a shallower depth. He nods, goes up about 10 feet, continues to swim a marathon, and then dives back down deep, going to 65 feet this time. Hmmm. Finally I catch up, signal up. He nods, does the same. FINALLY I give him a very assertive thumbs up and we head up to around 30 ft. After my friend and I were out of air (around 500psi), he decides to continue the dive alone because it's faster to get back to the entry-point that way. I wasn't going to stop him, as it wasn't my life in risk and I'm not his parent.
He even had the nerve to scold me for "diving unsafe" for removing my snorkel from my gear as it's something I never use. Go figure.