It's a good point.

I think the shock comes from being let down by another person that you trusted, relied on, or were vulnerable towards - and that betrayal hurt you.

The question is to what extent that person presented themselves as 'better than a sinner' and to what extent I projected that onto them instead.

At some point, patients in hospital show signs of improvement and progress towards good health. If the metaphor is to work, if church is effective as a hospital for sinners, then members should be making progress in sanctification for service, in mortification of sin, in bearing the fruit of the Spirit on branches pruned from the dead works of the flesh, in growing in the grace and knowledge of Christ, in having Christ formed in them, in going on to maturity, in being transformed by the renewing of the mind, and being conformed to the image of Christ.

We are not just sinners, we are sinners being saved in the present tense by grace that is effective - as well is in the past tense by justification, and in the future tense by resurrection.