My opinion is that Blair is an introvert and since he's paired with someone so extroverted, that can sometimes leave the introvert feeling pretty tired. In one of the extra scenes from the first episode, I think it was somebody on the last flight with Blair and Hayley who said that she was talking his ear off the whole time. Introverts recharge by being alone, while extroverts recharge by being with people, so in some ways I could see that Blair is in a situation that would be pretty stretching relationship wise.
I guess what I am trying to say (seeing as I am an introvert as well), that I can see that Blair might feel overwhelmed by Hayley's personality, but he might get used to it in time and they could become a strong team. I know that as an introvert, when I'm having a lot of new experiences and new relationships it can result in some sensory overload. Then, because I'm trying to process it all, I can sometimes be pretty reserved and quiet, which can come across as being cold towards others. I think they might warm up to each other over time.