Watch the birdie old-fashioned verb phrase
Now people often use "say cheese" instead.
It was said by a photographer when he would like small children to look at the camera and smile before he took a photo.
when the photographer said “watch the birdie”, all of us looked at the camera and smiled.
To be smiling very broadly, especially in a mischievous or self-satisfied way.
To smile in a slight way
1. Used to talk about a wide happy smile
2. Used to describe someone naked
The phrase "watch the birdie" as often as "say cheese" is an instruction given by a photographer to his subject, usually a child. Early photographers would hold a prop above the camera in order to gain a child’s attention, enabling them to photograph the child’s entire face. Often, these props were toy birds that would flap their wings or warble. In a time when children’s toys were simple rag dolls or marbles, such a toy would be a marvel. That moment of surprise was designed to stun the child into stillness, giving the photographer a chance to snap a crisp photo. Shutter speeds were much slower in the early years of photography. Today, photographers use a variety of toys to enthrall a child into sitting still for a good photograph. The phrase watch the birdie is now usually used for comic effect. (Source: grammarist.com)
Everything happens the way it should, especially bad things and there's nothing you can do and no reason to be sad about it.
I was first upset about my bad grades, but now I guess that's the way the ball bounces.