There have been countless studies on the subject to be sure. But everyone’s experience with caffeine is different. I’m interested in hearing directly from THIS group (HN) and can’t exactly fund a full blown study. So, asking for anecdotes!

This is an incorrect view. When you rule out anecdotes, you're ruling out specific cases. But specific cases are how we learn. You can absolutely learn from specific cases.

Moreover, specific cases are what studies are based on. And studies are often flawed, wrong, or misleading. You can often learn more from a few honest, specific cases than you can from studies.

People who work in modern academia can attest to the fact that studies aren't reliable in general. Individual studies can can be reliable, but you have to really know the field and sometimes the specific researchers in order to know what's reliable and how to interpret it.

There should be a name for the fallacy that wrongly absolutely rejects specific cases in favor of "statistical data," but I don't know if there is one.

Statistics can be just as obviously irrelevant to an individual as an anecdote to a big picture. A correlation between caffeine consumption and productivity or work well-being means nothing in case of an individual. Studies can't tell how individuals react, and I have a hard time seeing how a study would be relevant to OP in any way.

OP wasn't asking for statistics, or "the big picture". Of course anecdotes from other people can't really tell how things work for OP either, but I think they were looking for experiences that might be relatable.

You do realise most studies are just a collation of anecdotes.... They literally are what the big picture is compiled of....

I'd take a lot of anecdotes over studies any day. Studies gloss over the details (what kind of caffeine use, different physiologies, how they felt about the result) in ways that make them really difficult to use for personal decision-making.

statistics are saying that caffeine users are less productive

but statistics are only part of the story