The challenge I always have is to convince people not to invest in bitcoin. After all bitcoin is not an investment and it is not meant to give you profit. It is a currency and if you want to introduce it to someone you should introduce it as a currency too. That way they won't have a heart attack each time price has a sudden drop or a sudden rise while using bitcoin the way it was meant to.
They have interest to invest in Bitcoin when the market is very hot and they are very FOMO to join. Convincing them to cool down, stop their FOMO is very hard. Convincing them to not invest in Bitcoin when the market is heated a lot and might be corrected a lot is not easy. They probably think you are a bad guy who want to be rich for yourself and don't want to help them with your experience.
It is very painful experience so I myself don't talk with others that I am a Bitcoin investor. I keep it like a secret for myself and I will face with less challenge to be asked by other people.