There are two things that strike me from your post.
Firstly the quality of the training. What was average about it? Did they make it too easy for you, did you get the specialties that you wanted, please explain, I am interested.
Secondly you say the dives were uninteresting. With no disrespect intended, how many dives have you done? This is not supposed to be a facetious comment.
The reason I ask is that I am, since becoming a photographer/videographer, a muck-diver. Someone who is quite happy to sit under the boat on a dive site mooching around supposedly dead coral looking for small creatures.
I find the little things in the sea a lot more intersting than the really big stuff.
Two reasons, firstly they are easier to find. Secondly, they dont go anywhere - their territory is limited so they stick to it.
I have dived in the Med (Gozo) and I found it boring. Not because of the limited marine life, but because I was not allowed to stop and examine it. Hurry, hurry, hurry ... nah, not my fave sort of diving.
In your diving life, if you do a little research and find out loads about a couple of creatures, then when you go diving, you will search for these creatures to see if what the books say are correct! Then stop and look and watch them. It is very theraputic
Example. Me, done loads of dives, great places in the world, all over the place. My favourite sites - I love a couple of very simple dive sites off Hurghada (Egypt) that everyone and his sister goes to to do their training. Viz=30m, depth 10m. If I could, I would have stayed there a couple of hours just mooching around slowly checking out the cleaner shrimps, and the gobies.
One training session, I was teaching mask skills to a couple of open water students, and I saw a pod of dolphins!!!!
Boy! was the guy surprised when he had cleared his mask, the first thing he saw was a lumpy-great bottlenose swimming past!
When I was teaching, I could make a swimming pool dive sound attractive, so much so, that you would want to come back to the pool to do it again.
Consequently, if you, as an instructor are infectious in your attitude about diving and the marine life, it will rub off onto your students.
I feel sorry for you that your experience was not as it should be, maybe if I set up a LDS on Crete, I will post it and see if I can make it more fun for you