This person feels that he/she is so gifted , no one else can ever be better than him/her but realises that there's price to pay for being a genius and that is loneliness.

When someone says, "People can't keep up with me," he means that he believes himself to be unusually smart, witty, talented, etc. It is a bit boastful, and usually not true. But he IMAGINES that he is very special and that other people can't understand him because he is so smart; or that they are ordinary, so they can't appreciate his amazing creativity; or that he is always thinking of crazy things to do, and no one will join him.

Hello , That is funny:) Probably someone who says that wouldn't mean it literally. He is just kidding probably since he even didn't explain to you what it means pretending not to understand it. In general anyone saying that wouldn't mean it literally as mentioned above. He is probably joking or trying to tease you, unless he has some superiority complex as Erik explained to you.

Simply means that he is better than everybody.