The answer is by being a one issue Christian.
But let me start in the political world. I have to admit that Nicola Sturgeon is not my favourite politician. I'm sure she genuinely has many positive virtues and she is clearly a gifted leader and an articulate speaker; but she is SO boring. Whenever she opens her mouth what comes out is the call for another referendum and Scottish independence. It's made worse by the fact that she has a constant echo in Parliament which is the SNP leader Ian Blackford. I'm sure if the House of Commons was debating the price of orange juice it would be seized on by Ian Blackford as a reason why Scotland needs to be an independent nation.
I can't claim to be intimidated by Nicola Sturgeon, but that's because I've never personally met her. I feel sure if we were to meet up and I suggested reasons for not holding another referendum then I would be intimidated pretty quickly by her. Those who talk about just one thing are boring and when they won't allow any view, other than there own, to be properly expressed they are intimidating.
Believer be aware we can be like that. I've noticed it in three areas in particular.
Israel. I've met too many Christians for whom this seems to be the one issue they must talk to you about. And then it's even worse when they dogmatically tell you something you might not be convinced about, e.g. 'As you know this verse is clearly referring to Israel and how God will fulfil his purposes through that nation.' Well, actually, I don't know! In fact I have some clearly thought out views about Israel including what may be God's End Time purpose for the nation and certain convictions about the land. When I was an Elder in a large church in Brighton the leaders held slightly varying views on this subject but it never became an issue between us because none of us ever made it the one issue of our faith. I suppose because people perceived me as having a more 'pro - Israel' view than some others and because I taught a lot of eschatology it seemed to make me a particular target for a number of individual's views on the subject. I could then find myself both bored and intimidated by the way some insisted on making that the one and only subject they wanted to talk about. In fact, very often I then had an emotional reaction to this as I felt I wanted to take a totally contradictory stand on the subject to the person cornering me even if that was logically inconsistent. It's fine to have strong convictions on the subject of Israel but if it's your one issue you run the risk of being boring and intimidating.
Unity. Here's another one I've come across. Frankly, I think that evangelicals can be very weak about really engaging with this issue and I have sometimes spoken about it at leader's meetings. We can hide behind a phrase like 'the mystical union of the Body of Christ' but fail to give any real attention to the prayer of Jesus in John 17, 'My prayer is not for them alone. I pray also for those who will believe in me through their message, that all of them may be one.' vss 20-21. If being mystically one is all we need to be then Jesus didn't need to pray it. Surely it's a prayer that we might visibly appear to be one. But as evangelicals we can be very convinced that only our brand and expression of Christian truth is the right one which can feed into a spirit of separation. But when I meet, and I have, those who will talk of nothing else other than unity, and of course their way of it being expressed, then I find myself feeling a strong emotional desire to live completely isolated in my own church community! Unity, in my opinion, is a very important issue and we need to be much more proactive about it. But if it's the one issue you talk about then you risk becoming boring and intimidating.
Saving the planet. This is a more recent one as it reflects the current concerns about climate change. With all these one issue subjects there is of course some Biblical basis which can be used to support the intense commitment to it and interest in it. The doctrine of a new heavens and a new earth gives us some indication of God's clear investment in the physical creation. Finally, God will save the planet as part of his ultimate purpose in Christ. See Ephesians 1:9-10. Certainly this means that we should have a concern for the earth we live on and the environment that surrounds us. Let's play our part in not adding unnecessarily to the pollution of the earth and let's be careful not to squander the earth's resources. But for Christian's to become obsessed with this and make it the one issue of their faith as though they somehow can save the planet is again to risk being boring and intimidating.
For others the one issue is creation and evolution or the End Times or even the 5 points of Calvinism etc.
My concern is twofold. Firstly, that by being a one issue Christian the centrality of Christ is eclipsed. My second concern is pastoral, that if we become boring and intimidating other Believers will avoid us and the joy of fellowship is lost.