When I was living in China, I met huge - and I mean HUGE - numbers of people who were curious about religion. The church I went to was absolutely packed every Sunday, and I usually ended up standing at the back, unable to find a seat. At Christmas, every available space was crammed with people standing, and each pew had two rows of people in it - one sitting, one kneeling. I'd say maybe half the people there had a clue what was going on - the rest wanted to find out.
The occasions for sharing my faith were not always appropriately timed - for instance, on my return from Communion one Sunday to my standing position at the back of the church, I was accosted by the person standing next to me saying, "When you go up to the front, what do they give you?" Hmmm - what's the Chinese for transubstantiation...?
We had problems with some evangelical Christians who were not entirely honest. There was a big fuss when it was claimed that one of them had been deported for telling his students about God. Actually, that wasn't entirely true - he had been employed to teach business English, and had been using the Bible as his 'textbook'. He was sacked because he wasn't doing the job for which he had been employed, and as he had a working visa, he had to leave the country when he no longer had the work. Entirely reasonable, I thought - but he went back home to present himself as some sort of heroic martyr to the evil totalitarian regime.
Then there were the students from the big university up the road who would sometimes find their way to my flat, often in states of some distress. To a Chinese person, a teacher really is the fount of all knowledge, and someone to be hugely respected. There were two opposing 'Christian' factions among their teachers, each of which was telling the students, "If you don't join us, you'll go to Hell." Oh, and just for good measure, "If you join the other group, you'll also go to Hell, because we're right and they're wrong."
I spent many hours telling these students that the God I knew was a loving God, that I believed in Him and in the teachings of my Church whole-heartedly, but that they should not feel pressured to join any church at all unless and until they understood what it was teaching and believed that those teachings were something that they wanted to follow.
Funny - the best witness I could give for my Church was to tell people I didn't expect them to join it. That way, we were able to have a proper discussion about the religious, social and moral teachings of my Church and why I accepted them. Knowledge is power, and armed with that power, some people chose to find out more about the faith for themselves. I like to think that in this way, I may have planted a few humble mustard seeds.