I often run across people using ŝanĝi as though it were intransitive — in a sentence such as la situacio *ŝanĝis rather than la situacio ŝanĝiĝis or li ŝanĝis la situacion. We tend to do this because in English we often (though certainly not always — compare to kill and to die, for instance) tend to use exactly the same forms for transitive and intransitive verbs with related meanings. One does not do this in Esperanto; each verb has a specific meaning, which may be intransitive (it shows what's happening to the subject of the sentence) or transitive (it shows what the subject is doing to the object of the sentence). There are specific suffixes (-ig- and -iĝ-) to change intransitive to transitive and transitive to intransitive, respectively.
There's a potential flaw in the system in English. Take the verb to drown. Consider a man who makes his living drowning unwanted cats, dogs and pet rats. When asked "What do you do for a living?" the obvious answer is "I drown for a living." Obviously, here to drown is transitive; but structurally the sentence is showing it as intransitive. We have to depend on external knowledge to suspect that he's not saying what he sounds like he's saying (you only drown once).
David Jordan, in his book Being Colloquial in Esperanto, lists several verbs that give English speakers trouble in this regard. You can find slightly expanded lists of his on the internet for transitive verbs and intransitive verbs in Esperanto.
I note that many American Esperanto speakers translate "to note something" (as "to take note of something") as noti.
noti basically means to make a semipermanent record of something, either on paper or in one's memory or whatever. "To note" meaning "to take note of something" is rimarki, and we should remember this.
In a recent review of Ronald Cecil Gates's short mystery novel Mortiga ekskurso (Fatal Excursion), reviewer Donald Broadribb of Australia asks (translation is mine):
I noticed, while reading the work, that the recent custom of using forms such as -atis, -intas, -intis etc. leads to the appearance of verb forms intentionally omitted from Esperanto by Zamenhof: the perfect, the plusquamperfect, the imperfect et al. Is this a genuine enrichment of the Esperanto verb system? I'm not sure.
Conservatives have been railing against these forms since before I learned the language. If I suspected that they would become commonly used, I'd probably rail against them myself. But it should be noted that, because of the structure of the language as defined by Zamenhof in the Unua Libro, these forms are in fact intrinsically part of the language, even if Zamenhof never found it convenient to mention them explicitly, or use them in his own works.
They can legitimately be used. They should be used sparingly.