I never feel groggy the next day. Always wide awake and refreshed like I got a good nights sleep.
I did eat a whole bag of chocolate Reisen once. For a long time I believed I had eaten the wrappers also. I found the empty bag by my bed (on the floor

) but no wrappers anywhere. I even searched the trash. Then, about a month later, I was unpacking my Christmas decorations and found all the wrappers shoved in one of the boxes!!! It would have taken quite a bit of effort to get to the box and put the wrappers in it so I must have wanted them in there really bad.