100% agree. There are no hard and fast rules. The very same person might be happy to chat one day and want complete silence the next. I once boarded a 2am flight after being awake since 4am the previous morning. I was exhausted and just wanted to doze for six hours. I found my seat beside a young Thai woman curled up against the window with her hoodie over her face. Perfect, I thought, we'll both keep to ourselves. The meal service woke us both. Somewhere through the meal a completely natural conversation started, and neither of us stopped talking for the next four hours. We even carried on chatting while waiting for our bags after landing - it felt like the flight lasted 20mins... She'd just graduated in the US and was flying home. We swapped travel stories, talked about life, and the conversation simply flowed, if flowed really well. I was twice her age and married, so there was never anything beyond an enjoyable conversation between two strangers - I was worried she'd ask me for my line ID - I'm married, was nearly twice her age and she's simply a girl having a chat with a seat-partner on a flight - she just wanted to talk and I was happy to join in - the conversation just kept on 'clicking'.... That's why I never dismiss talking to people. Some of the most interesting people I've met have been completely by chance. The key is that it has to happen organically, and you need to read the cues. If someone's putting in their earphones, opening a book, turning away or giving one-word answers... they're telling you they'd rather be left alone.