@marba Well, theanine and caffeine are technically the same, but L-theanine has several beneficial effects in the brain, which give a relaxed state of mind. That is why you can drink a cup of tea in the evening. Some people cannot sleep after drinking coffee but some other people can. It depends on the sensitivity to the caffeine.
And about having the coffee shake AND coffee during the day, I feel you! Personally, I like to mix the chocolate with the coffee shake (one spoon of each, mocha style ), then I am getting less caffeine and I can have an americano later in the afternoon. Thanks for your suggestion! It will be shared with our team.