This is my first post on any forum so hopefully I've done this correctly! 

Background info:  Walden is a 14 week old, male tri-color Pembroke.  He's a generally happy and active little fellow.  He loves to be petted, rolls over for "tummies" and loves to go for rides in the car.  He snuggles when he's tired, gives kisses and has a sweet personality.  He's in week four of puppy class at Petsmart and is doing very well.  He's very, very smart!

But, my darling little guy has a ferocious side!  I'm hoping this is a phase or a "terrible twos" sort of thing.  But, Walden can on occasion get himself really riled up and will bite!  This seems to happen mostly to me, not as much to my husband.  And, it's always in retaliation for stopping him from doing something that he wants to be doing.  For instance, if we're playing in the backyard but it's time to go in, I'll call him to me and he will come most of the time.  But, since he doesn't have his leash on at that point, I have to pick him up to take him in the house. (backyard is detached from backdoor.)  When I go to pick him up he starts snarling and snapping.  This isn't a happy thing at all it's a massive protest.  Even when on the leash and we're heading back into the house and he doesn't want to go, he'll attack my shoe or pant leg.  He's also done this during puppy class when he's prevented from playing with another puppy.  If we restrain him he'll snarl and try to bite! 

We're trying the ignoring concept which works temporarily but he hasn't really improved.  We might have a "grouchy" incident about every other day and always when he has to stop playing. 

I'm very worried that he's developing a very bad habit.  We love him so much and he's making excellent progress in all other ways besides these terrible tantrums.

Any advice would be greatly appreciated.  He's a really good and sweet dog until he decides to be nasty!