An angle class II malocclusion is worsened by:
CLINICAL SIGNIFICANCE
Angle's Class II Division 1 Malocclusion (Distoclusion)
Molar relation: The lower dental arch is distally positioned in relation to the upper arch. The distobuccal cusp of the upper first permanent molar occludes with the mesiobuccal groove of the lower first permanent molar. 
Class II canine relation: The distal incline of the upper canine occludes with the mesial incline of the lower canine.
Line of occlusion: This will be altered. Other features of Class II division 1 are:

V-shaped or constricted maxilla
Proclined maxillary incisors
Lip trap
Exaggerated Curve of Spee
Deep bite

Class II division 1 subdivision: This is a condition where the Class II molar relationship is unilateral or present only on one side with normal Class I molar occlusion on the other side.
Key Concept: 
The mandibular deficiency worsens the class II condition. In such case, treatment should aim at reducing protrusion of maxilla and in meantime augmenting the growth of mandible.
Overclosure
Short facial height
Decreased mandibular growth
Decreased lip activity