Any abstraction can be taken too far, but I think templates tend to be particularly attractive because it is both mentally challenging and can easily produce huge volumes of code. It makes those who enjoy overcomplicating things feel productive. The same can be said of things like design patterns and "OOP extremism", but templates give that extra flair of "expertise".

On the other hand, I'm the exact opposite. I hate overly complex solutions to intrinsically simple problems. I use abstractions sparingly and only when they reduce overall, not just local complexity. Sometimes moving down a level of abstraction or two will yield a better solution. Write simple code. Focus on programming and solving the problem, not metaprogramming and the metaproblem. If you're spending weeks to write (and debug!) a huge "generic solution" spanning a dozen files and several thousand lines of code which someone else could do in an hour with a few dozen lines of code in one file, I don't think that's being clever at all. I've personally experienced this, being that "someone else".

The C++ purists will probably find this repulsive, but in some cases a macro will be the far simpler solution. What templates can do are not a strict superset of what the preprocessor can do.

"All problems in computer science can be solved by another level of indirection, except those caused by too many levels of indirection."