just plain bored with having nothing to say but the same small talk everyone else is making.
this is indicative that you are paying attention to the topic/words of the conversation, rather than the sub-communication, which is often the interesting bit for these kinds of conversations. People who can't read social cues and sub-communication typically don't get why others find small talk so "interesting", but this is rather like a radio that sends the carrier wave rather than the signal to the loudspeaker. The topics are just there as a "carrier wave" which is then modulated to encode social signals.
Sub-communication includes agreement/disagreement (someone agrees with you to signal alliance, disagrees to signal enmity), tone of voice (tone that rises towards the end of the sentence indicates submission, tone that falls towards the end conflict/assertiveness/dominance), body language, who gets to talk most/who listens most. Once you tune your radio in, you may find such occasions more exciting.
Tuning in to the carrier wave in social situations is a common failure mode for smart people, because we feel comfortable assessing factual statements.
Once you tune your radio in, you may find such occasions more exciting.
What I usually dislike about the small talk game is that it's often played by people who don't know each other well and/or by people who are so conformist as to be intrinsically boring. It's one thing to measure alliances among fascinating, dynamic people who are out in the world doing and being things. I would be more than happy to listen to say, Dan Savage, Janet Napolitano, and Max Tegmark make small talk. Ditto people in their 20s who were correspondingly less accomplished but...
Followup to: Do you have High-Functioning Asperger's Syndrome?
LW reader Madbadger uses the metaphor of a GPU and a CPU in a desktop system to think about people with Asperger's Syndrome: general intelligence is like a CPU, being universal but only mediocre at any particular task, whereas the "social coprocessor" brainware in a Neurotypical brain is like a GPU: highly specialized but great at what it does. Neurotypical people are like computers with measly Pentium IV processors, but expensive Radeon HD 4890 GPUs. A High-functioning AS person is an Intel Core i7 Extreme Edition - with on-board graphics!
This analogy also covers the spectrum view of social/empathic abilities, you can think about having a weaker social coprocessor than average if you have some of the tendencies of AS but not others. You can even think of your score on the AQ Test as being like the Tom's Hardware Rating of your Coprocessor. (Lower numbers are better!).
If you lack that powerful social coprocessor, what can you do? Well, you'll have to run your social interactions "in software", i.e. explicitly reason through the complex human social game that most people play without ever really understanding. There are several tricks that a High-functioning AS person can use in this situation: