Joyful Photography

I spent a good deal of time last night looking at the work of another photographer whose models all looked really happy. It made me realize that I have so few photographs of people looking happy. This isn't on purpose mind you. It's just instinctive for me to want poses and expressions that look either neutral or serene, and I feel like if I try to force a smile out of someone it is just going to look fake.

I am curious how this other photographer (who I shall not name) does it and makes it look real. I admire that simply because I'm not sure I have that skill as a photographer. On occasion I can capture genuine joy in a person, but I feel like I'm just getting lucky when I do. 

Camera: Mamiya 645e
Film: Kodak Tri-X
Location: Portland, OR - Sauvie Island