THEME:   phrases change meaning with the addition of the letter B   
GOOD ONES:     Where to find wool?   ON-THE-LAMB   
Title for Shakespeare?   IAMB-LEGEND   
Like a door[way] with three peopleā¦?   JAMB-PACKED     
Lose on purpose   DIET   
Great way to have it   MADE   
Delivery man?   MESSIAH   
Isn't expanded?   IS-NOT [I think the question mark lessens the fun]   
Mating game   CHESS   
Strained-carrot holders   BIBS [because babies make a mess]   
Track figures   ODDS [I thought touts, etc.]      
BTW:   Troubling spots   ACNE [this would have been good if the common phrase "trouble spots" were the clue]      
Take a hike   SPLIT [well, maybe for the AARP crowd for whom split meant leave, but on one's own accord.  "Take a hike" is a command.  Anyway, I think the term split has split, so the clue might better be "Leave, once."]         
RATING: 
 
 
   Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun