"Come to church on Sunday with me. It'll be a blast."

It turns out that among all the invitations you are likely to overhear on a crowded train, that is among the most unlikely.

We don't like inviting our friends to church, according to new findings from Christian Research. Furthermore, though we like to blame the church for that – we'd like to wait until both the services and the congregation are absolutely perfect first – there are more deep-rooted things going on, with a fear of personal rejection at the heart of it.

The research was unveiled by Michael Harvey, whose Back To Church Sunday initiative was spectacularly successful in its early years. Here I declare an interest: when I was the editor of The Baptist Times a few years ago I was partly responsible for getting my denomination to adopt the scheme. Hundreds of churches took part and thousands of people have returned to church because of it.

Harvey is an impressively entrepreneurial and creative Christian thinker. However, I wonder if his research quite tells the whole story about why we are so reluctant to invite people to church.

The thing about churches, especially of the evangelical variety, is that they are all-absorbing.We expect total commitment or nothing. There's no middle way. Someone appears for the first time, doesn't know the songs and is obviously a bit out of their depth. Have they enjoyed it? Will they come back? They appear next week, and possibly the week after that. Then they don't come for a month. What's going on? Have they been gloriously converted, or not?

Actually, they might just have been busy. Because what regular churchgoers who are thoroughly embedded into a church don't realise is the extent of the culture shift that it requires of someone who might have been used to an entirely different pattern of life.

Just getting up and coming out on Sunday morning is quite an ask. Doing it every Sunday, when there is so much competition for people's attention, is huge. Then there's the prayer meeting and the housegroup. Then there's the sense of responsibility: a working party to clean the church or decorate the hall? Why, thank you very much, we'd be glad to have you.

No wonder Milton Jones' famous joke got so much Christian traction: "Some people see the church as a giant helicopter. They're scared to get too close in case they get sucked into the rotas." Or how about the old favourite: "Mary had a little lamb, she also had a sheep/ And then they joined a Baptist church, and died from lack of sleep." Insert your denomination of choice.

The thing is, there's nothing intrinsically unreasonable about all this. We believe in commitment. We believe in community, and in discipleship as part of a wholehearted involvement with the people of God. Evangelicals believe in conversion, and there's got to be a change in behaviour as part of that.

But perhaps part of our reluctance to invite people to church is a reluctance to impose such a crushing burden upon them. We know what we're offering, but we know what it will cost, too.

As well as the cost to them personally, there's the cost to our relationship with them, whichever way the invitation goes. Maybe we're neighbours who chat over the garden fence. Maybe we see someone a couple of times a week in the gym. Either way, the relationship is what it is, and we're quite comfortable with that.

Maybe, actually, we quite like having a life outside church – not much of a life, maybe, given that it's a black hole whose massive gravitational pull attracts every moment of our time and every particle of our energy – but we do rather enjoy having conversations that aren't about church. We're awkward about moving things on to a different level. If we invite them to church they might think we're weird, or have an agenda, and not come. If they do come, and enjoy it, and we start meeting them at house groups and prayer meetings, that might be even worse. So really, why would we?

So here's a thought. Why don't we think a bit harder about what we're actually inviting people to be part of when we ask them to come to church? Suppose we accepted that it's more healthy for people to have wide interests and an active social life that will take them out of church life? Instead of wanting people to sign up to a whole cultural package, in which their social circle, their pastimes – even their tastes in music and films – are dictated by a need to show their commitment by supporting meetings (and here's a thought – shouldn't it be the meetings that support the people?) why don't we just relax a little, and accept that people can love Jesus even if they aren't in church?

I'm from a church tradition which values belonging. Most churches are like that, and conventional evangelical wisdom says that strong churches are the ones that attract strong loyalties and have clear boundaries. I want to challenge that. I want to argue that really strong churches are confident enough in themselves and in Christ not to need to guilt people out if they aren't there.

I'm all for commitment, not least for purely selfish reasons: if I've laboured over a sermon I'd rather preach it to a full church than an empty one. But I'm also for fuzzy edges, giving people time and space, letting them make their own way into faith rather than piling expectations on them, and not confusing discipleship with church attendance.

And maybe if we were more relaxed about church, we'd find evangelism easier too.

Follow @RevMarkWoods on Twitter.