I would do triathlons except _______

I occasionally go on auto pilot during conversations.  I give the appearance of an attentive "active" listener but I'm most likely thinking about food. 

There are certain triathlon related conversations which seem to repeat themselves and follow a predictable theme.  The person typically explains why they choose not to do triathlons.  The person ends with one of two explanations.

I would do triathlons except I can't RUN (goes on to explain knee problems)
I would do triathlons except I can't SWIM (goes on to explain maternal grandmothers fear of water)

Well, I was busy thinking about food as the person I was talking with started the magical phrase which allows a person not to participate in triathlons.  It was at this point that I was genuinely suprised, a bit delighted for a new option and once again engaged in the conversation.

She said, "I would do triathlons except I can't BIKE"

Who can't bike?  Kids ride bikes!  - now if I really had been a better communicator, I would have refrained from asking those two questions.  I would have said, "Interesting, tell me more"  but instead I chose to belittle. 

There really wasn't much of an explanation except the person never really learned to ride and doesn't like speed.

I guess I now have heard it all!