That the mind reading toolbox has never become available for general use? ;-)
Truly, that scares me just a bit if it ever truly became a reality, so not a real frustration.
So what frustrates me? As new capabilities are introduced into new releases, we find that the old tools stay around. This is necessary for backwards capability. And backwards capability is one of the things that makes MATLAB truly great, that I have nearly 35 year old code that still runs. But that leaves us with bloat, in the sense that we now have multiple tools with similar capability. New users find more stuff to learn. The result is a language that is not as clean, not as easy to use as I want.
For example, we have both strfind and findstr. If you read the help for findstr...
findstr is not recommended. Use CONTAINS or STRFIND instead.
But findstr remains in our universe. One day it might disappear. But when you want to use a code to do that, does anybody really remember which of findstr or strfind they SHOULD use? Which is the recommended code, which is deprecated?
I can offer other examples. We have delaunay, delaunayn, delaunayTriangulation, and triangulation. We even have alphaShape, which can be made to produce a delaunay triangulation if you know how to use it. But not all of those tools are truly compatible with each other. What are the differences? Sigh.
How about interpolation? There is the interp1/interp2/interp3/interpn family. But then we have griddedInterpolant. A different tool. Not compatible with the others. And griddedInterpolant requires an ndgrid call to use it, whereas the others rely on meshgrid. Sigh. While I prefer ndgrid to meshgrid because of the x/y inversion issue when you go to n dimensions that surely confuses people, but this difference will surely cause problems.
Likewise, for scattered interpolation, we have griddata. But then we have griddatan. We have scatteredInterpolant. And as confusing, there is no griddata3. griddata works in 2 or 3 dimensions. So they do similar things, but new users then need to learn about 3 tools.
There are other examples. For example, some toolboxes introduce capabilities that already exist in MATLAB. So if you have the correct toolbox, then you get a tool that replicates functionality that already exists. Yes, the new tool in that toolbox probably adds some new feature the author thought was useful. But again you have a source of confusion, especially a problem for newer users. An example of this is xcorr versus crosscorr. You get one from a toolbox.
Yes. I understand the reason for the various tools. But the result ends up as bloat. If I want to do X, then there should be a direct way to do X, ONE way. Not 10 ways, all of which have subtly different interfaces.
Is any of this really a major problem? Well, no. You learn how to use what solves your problem. And gradually, you learn about the alternatives.
I still love to use MATLAB. I just wish it were slightly more perfect.