That's when we start to question whether reward training actually works without some form of punishment. 
How does positive training work when the dog is ignoring my cues and "trying to get away with stuff"? Especially when he's not coming when called. Or decides to go sniffing when I sent him for a bumper retrieve?

That's the topic of this article. I used a different format than normal. This is a real letter I received this week. I changed names etc to keep it generic. And I typed my responses into the letter with GREEN font, between each issue listed. 

• He doesn't come to the command or whistle the way he did a couple months ago.  Wants to hang out and do whatever he wants to do.  I sometimes have to go get him to get him to "come" back to where I wanted him.

• He clearly knows how to fetch, but often now he will run to the bumper, mouth/nose it around a bit and will then lay down and chew on it.  I try encouraging to "fetch", "come", blow his whistle retrieve, but he will just continue chewing.  Most of the time with this, I give up and walk over to him to get the bumper.  I don't "reward" him on this, just grab the bumper and walk back to our starting point.  He generally follows, but sometimes wanders around to check smells/etc.
   
• Did you do a training process to proof the formal retrieve? Such as the Fetch & Hold course in field puppy? If not, do that. Again, you and your cues are in now in competition with his ever increasing world. When you were 14 yrs old, you saw the world and interacted with the world differently than when you were 8 yrs old. For lots of reasons. Same is going on with your pup. 
  So even if you have taught the formal retrieve - or even if Hank has a natural retrieve - your cues and rewards are in competition with the world. Work through this with compassion by again,
  1) re-build the bank account for retrieving on cue, in a low stimulating environment with HIGH value rewards and short distances. 
  
  2) Get in reality about what he is capable of right now as he goes through this massive change. Don't ask for what you won't bet $50 that he will do. 
   
•  3) Teach the formal retrieve lessons, if you haven't already. 
   
• A few times he has run to the bumper, picks it up and then wanders around, smelling, finding something to dig, etc.  Again, I try to call him/etc, but he just does his own thing.  I slowly walk to him, but then he wants to play chase, which I don't engage in.  I just walk back to our starting point and wait. 
• Good - and now also ask yourself, what are you using as a reward? Is the act of doing the retrieve, rewarding enough to return to you? Or is it more rewarding to wander off and smell or dig? 
  1) use the formal retrieve lessons
  2) Go back to food bowl marks lessons and figure out how to reward the return so the return becomes automatic and fast. 
   
• He does a good job with the casting to food bowls.  90% of the time running to the correct bowl and returning to me.  Occasionally running to the wrong bowl or running to a second bowl after going to the correct bowl.  I am less worried about this, but it might be part of his adolescence. 
  
  Take heart that this will pass. But your job is to be a great coach and relationship to him in the interim. Rules of thumb with every challenge:
• Set up a low stimulation environment and re-build value for the thing you do want.
• Prevent rehearsals of refusals, by not setting him up to choose between a higher value environment and your boring commands.
• Find ways to transfer the skill again from the low stim environment to new places, with success you can build on.