Preaching should be about bringing the 'good news' of salvation to the lost, and about teaching disciples to 'obey all that Jesus commanded' (Matt 28v20). Preaching can hurt the church in a very negative sense when it stops being based on a straightforward exposition of the Word, and slips into the preachers platform for venting his own frustrations, feelings, and opinions. However, even if you stick to the Word, it can sometimes 'hurt', but in a positive sense. This is when it brings a Holy Spirit conviction regarding sin, leading to repentance. If somebody is hurt by the Word but it leads to a change that makes them more Christlike, then that is a good thing.
As a preacher, I try to keep myself in check by listening back to myself to help me to improve the clarity of my delivery, and by encouraging discussion of the message in mid-week home groups. That way, the church has the opportunity to challenge what was said (in a non-confrontational way, I should add!), so that nobody is put in the position where there they have to simply swallow what was said without question.