Responses to thank you

I had a strange thought when I was returning home from breakfast and I kept the lift door open for a neighbour ...

If a person thanks you for doing something (like holding the lift for them), the polite responses should be:

1. You're welcome.

2. Nah, it's nothing.

With "you're welcome", it is an acknowledgement that I did SOMETHING for you that I did not need to do but I would do it again.

However, the second response, which I much rather prefer, means that it was such a minor thing that I did not expect thanks for it. Is it false modesty? Perhaps. But I do get a tinge uncomfortable when I respond "You're welcome". Why? Because it implies an ongoing commitment to extend the favour indefinitely which is pretentious and situational. 

Am I weird? Yes I am. And "You're Welcome" for this blog post.