Be boring rather than arrogant. If they ask what you did this weekend or what you’re doing later just say nothing really or watching TV and relaxing. Few words answers, when the conversation isn’t flowing naturally they will just think you’re boring and leave you alone.
Obviously this might not work for everyone but it’s worked for me everytime.
Depending on what you meant by “very easily impressed with basic factual statements” it could go either way. I’m an adult and I’m happy to admit I don’t know a lot things, sometimes I’ve been stunned that what I believed was totally wrong and all it took was some to give me a basic fact to make me realise.