What have I learned from this addiction? That when playing long games of chess, not to rely on my instant sight. When I see a move I should forget about it and think again.

Good advice, and something I myself strive to meet. Too often players go for the obvious, and too often miss getting set up. 

I like your comments on the Tactics Trainer. Keep up the good work! 

When I play too many problems in succession I begin conflating positions.

I have an idea for a new modification of the game: let the computer calculate

the values of the position (say at 2500 strength) before and after the player makes the move and also for the "answer" present that value of the "answer" .

I suppose there would have to be a much larger interval in real time between each step because of the data load but it would be interesting.