Instead of telling others what bitcoin is, it's better to go through what we get from bitcoin, and receive a very satisfying result. Later on by other people will ask how you get it all, from there we can explain what is bitcoin on them.
There's nothing you have to do to convince them, just leave them alone. They are people who are never ready for change and never listen.
What do you expect from them? Do you get some benefit from it? This is useless and Bitcoin doesn't need people like them.
Just do what you have to do and try to make a profit from there instead of wasting your time with those people.