When people notice my phone's language is set to English, most of them react by saying: "Oh, you think you're smarter than me?! Is that it? Is that why you set it to English? To feel smarter?".

And the truth is... no! Of course not.
The real reason is much more practical. A close friend of mine thought it was stupid — well, not stupid but... a solution to a problem that doesn't really exist.

My idea is that the iPhone is an American phone, and its OS is developed by Americans... English speaking people. This means that its interface is planned and designed to accomodate English textual elements, not Italian ones.

Take birthdays as an example. Let's say today is Cristina's birthday, the widget would say "Cristina's birthday", right? Right. In Italian that would be "Compleanno di Cristina".
See how much longer that is? Also, the name goes at the end of the sentence, and this is a huge problem, especially on my tiny screen (I have an iPhone mini, btw). The text gets cut because it si too long, and all that I see is literally "Compleanno di ..." which is completely useless, and it drives me mad.

Another example? The "Shortcuts" app is called "Comandi Rapidi". Ugh.

To me this is a serious issue. I need the phone to serve me as best as it can, and for that it needs to be able to display as much information in as little space as possible. English takes up much less space than Italian.

And you know what? For years now (ever since I switched to Linux back in 2018), my pc language has also been set to English. I'm used to it, I don't even notice it anymore.