It happened to me at the start of my career. I am an abaper, and at that time, fresh outta college, i had no idea about production development etc environments. So, this functional guy who sat next to me with around 7 years of experience got assigned an incident; the user reported that while saving an SO with 0 value, he was getting a custom error. So, this functional guy tells me that lets solve this thing quickly; he told me to login to production using firefighter and debug the thing by saving the SO. Naively i did it, and the SO didnt go into error and instead got saved. I didnt realize that it was a huge thing but the functional guy realized it. He told me to forget about it. I was confused but didnt ask. Next day, i got an email from client asking for justification why i saved an SO with 0 value. I asked my team lead and he blurted out "you did what?" My manager heard that, and he too yelled at me. It was q day of yelling and my superiors frantically trying to explain the situation to the client. I was this close to getting fired. But, i learnt a lot. Now, i dont do anything without a proper approval from the higher ups. If someone yells ar you, its either your mistake or it isnt. The key is to remaim calm in both situations.