Giggles are good for you. They just might be even better for you than laughter because they're that small step towards laughing that begins the process of giving in to joy. They're the build up to deep belly laughs that shed tears because of an inability to contain the happiness within.
Giggles are a sign that everything's ok again. Ever try to coax a child to stop crying after he gets hurt? That little moment of hesitancy, between tears shed for sympathetic attention and recognizing the humor of your antics in an attempt to repair happiness, creates room for a giggle. Quite often, a giggle is the sound that will escape when a laugh is suppressed. Giggles are harder to contain, they wriggle out and air themselves much too late to be snatched back and kept in check.
Don't be fooled, guys do it to, but generally under the more manly sounding moniker of a chuckle. Regardless of what you call it, don't suppress it. Give into joy!
1 Thess 5:16 Rejoice always!
Psalm 100:1 Make a joyful shout to the Lord, all you lands!