I wouldn’t want to speak for all strange bewhaviors.
However, the laughter, is, to me, obviously from The Lord.
We have laughter routinely in our congregation. Usually, the more the
MANIFEST PRESENCE OF THE LORD IS THERE, the more likely it is . . . depending. SOME types of the MANIFEST PRESENCE OF THE LORD LEAVE EVERYONE FEELING AWED AND
WOE IS ME A MAN OF UNCLEAN LIPS . . . WITH UTTER SILENCE BEING THE NORM.
I have experienced the laughter myself. It came out of nowhere and I don't believe it was from me.I had never heard of it as a manifestation of the Spirit until much later when I read about it and realized what had happened. I was alone at the time so it didn't happen as a result of other people doing it, or of trying to be seen- I had never seen it nor heard of it before. I don't speak in tongues either. That's my experience of it for whatever it's worth.
It was a very healing and beautiful experience, so I do believe it came from God.