When Diving is not Fun!!!

My frst three days of diving here in Cozumel were quite nice. We chose Aldora divers to dive with for the week. They cost a little more, but what you get in return is definitely well worth it. Everyday when the boat gets to the dock of my hotel, my gear is set up and ready to go (and rinsed and put away at night). They use Steel 120's instead of Aluminum 80's. This gives us nice 80-90 minute dives (depending on who you are with). They also use fast boats and limit groups to 6 (no cattle boats with 20 divers getting in your way). We had different divers in our group the first three days. They went through their gas much faster than myself so we ended the dives based on their limitation, but it wasn't too bad (and they were all very nice friendly people).
Then came today. There were two pople in our group that were absolutely disasters in the water. Now remeber, with tip, I am paying $100 per trip to dive. On the first dive, I could not really enojoy myself because I was making sure another diver was going to live through the dive. She was using air (21% O2) and had her computer set at 50% 02. This will do two things to your computer: 1) think you are going to convulse because of your PO2 level 2) Give you way more bottom time than you actually have. Her dive buddy was on air and was using the exact same computer. He started to ascend 10-15 minutes before she did. I was curious so I went to check her computer. I knew she had flown by the No Decompression Limit so I stayed with her and had her ascend with me and made sure she did a 15 minute stop at 15-20 feet. She still had no clue what was going on, which confirms my point. Wasn't this the job of the dive master??? You would think so, but he was too busy attending to the other disaster in the water. We came up about 30 minutes before I was ready (bottom time and air comsuption).
The second dive should have been 80-90 minutes. We started our ascent at 50 minutes. The other disaster I mentioned before got in trouble for basically trying to ride a turtle. The divemaster told us 3 or 4 times we are in a protected marine park. We pay for the priveledge of diving in the area and are not to touch anything. However, this diver didn't seem to ever pay attention to any authority or any one else for that matter. I started my ascent with 2000psi (which I like to get to at least 800 before calling it quits). We were at the safety stop BECAUSE OF HER, and THEN SHE DESCENDS TO 45 FEET AGAIN TO LOOK AT A NURSE SHARK. So selfish and clueless.
So the dives were not relaxing and I kept my head on a swivel. I was not the divemaster, and they are certified divers and responsible for themselves, but being a responsible diver I knew it was my duty to help ensure safety.
"Hey Chad, aren't you in the middle of the divemaster class and want to become an instructor?" Yes!!! I love assisting divers that are struggling or want to learn. However, you get paid for that. I was paying $100 for a relaxing nice recreational dive. I don't mind helping out others for free that are willing to learn, but these two showed that they have no interest in improving their water skills.
So Aldora does their best to match up divers of like experience and skill. My first day,they didn't care of what I said, they wanted to see me in the water. It was a little frustrating. However, now I understand. People go into their office and feed them a bunch of B.S that no where close represents their water skills. So, rough diving day, but still receiving great service from Aldora.