THEME:   13 phrases comprised of two words, the first beginning with P and the second with G   
GOOD ONES:     Title:  PG-13   -y plus -y   IES     [I thought algebra, not plurals]   
Subject with no depth?   PLANE-GEOMETRY   
Where to see an inflation index?   TIRE-GUAGE   
Bold type   DARER   
Motor add-on?   OLA [elctronics co.]   
Dixie group?   Y'ALL [where I live it might be "all y'all" for a group and just plain "y'all" for a person]    
Computer terminal?   ESE      
BTW:   Ticked off   MAD [colloquially yes, but MAD is insane; "ticked off" is angry --- how about "Cap or magazine?"]      
Recess 
near an altar   APSE [the altar is 
in the apse]         
RATING:    
 
 
Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun