I've seen the claim that "programming languages are just tools for telling computers what to do" quit often, and I think it really misses the mark to the detriment of whoever believes it.

Programming languages are "just" tools for expressing ideas. Ideas that a computer can then run. A programming language really is a language and it ultimately affects what you can easily say, how you say it and even how you think about problems. Put another way: semantics are important.

Of course, if you only know one language well and you believe it's just a way to direct your computer, you won't realize this.