Richard Carlson advises us to look beyond the overt behaviour and try to understand what might lie behind that behaviour. If a loved one snaps at you does that mean they no longer love you, of course not. It may simply be that they are having a bad day. If a stranger doesn't live up to our expectations it may be that we've set them too high.
I am reminded of two of Don Miguel Ruiz's 4 agreements when I read this - Don't make assumptions and Always do your best.
If we can recognise that there are days when we don't really perform up to our own expectations we should also then remember that sometimes other people can have bad days too. If we can remember that, then any irritating behaviour that makes us angry or anxious can be put into it's proper perspective.