My pet peeve is when I have an application crash and the error message has been translated. Now googling it is extra fun, not to mention bug reporting.
Fortunatly with Linux, I usually can get the proper message with "LC_ALL=en_US.UTF8" if I can, and desire, repeat the exact same error.
Now I understand that this is done for openess and diversity. But technical terms should not be translated. I'm french, and I accept that english has won as the business language, and the IT language. Let's move on.
Honestly, we are wasting humanity potential for not having a common language. I really, really wish we would all learn english as the second language, and that all laws, forms, labels and signs would be translated to english everywhere (as an addition to the local lang, not a replacement). It's an imperfect language, but it won half of the world, and the other half will have an easier time learning it that us learning theirs. Plus it has a very simple alphabet, and is already used for science, business and international politics.
At this stage, I would gladly agree for all the french books and movies being burned and lost forever if it means one language, any language really, becomes magically the main one for humanity. We have too many communication problems.
But since magic doesn't exist, what about getting off the ego train and just adopt the imperfect status quo and make something awesome with it for a change ?