I found that written and spoken French can be two different worlds — and i’m not talking only about passe compose. But even saying “nous faisons...” is just in the written world — you use “nous” a lot in a restaurant and they’ll know you’re a foreigner. They use words like “on fait” instead. Why? i have no clue.
I believe it is because you are removing yourself from the action/opinion/occurrence (whatever) to avoid responsibility. The same thing occurs a lot in Spanish. You normally don't say "I lost the book" (Perdí el libro), but "The book got lost (to me)", (Se me perdió el libro).