for sure. I have faced many an angry, having a bad day, immigration person behind the glass and the best thing to do is to follow all the rules have your stuff ready and set it on the counter then take a step back and listen carefully for anything they may ask you. If you cannot hear them, then and only then, do you approach the counter. Often, these people are ex or current military and they are accustomed to extreme protocol and if you don't give that to them they can become unreasonably upset. Get under their skin and they can find something wrong with your visa if they really want to. You have ZERO guarantee of entry just because a consulate gave you a stamp in your home country. Ultimately the person behind the glass has all the authority that they choose to take and press them the wrong way and your are going to FAFO.