One of the hardest things that we do as humans is offer to ourselves compassion. It is easy to offer others compassion, but when it comes to me, I rarely qualify.
I think that when Peter wanted to refuse to allow Jesus to wash his feet, this same principle was at work. He was not about to allow himself to receive something he did not deserve.
I think this tendency to not offer ourselves compassion also creates in us stress which then causes behavior that we would not intentionally set out to do. For instance, when my wife asks me a question like when am I planning to till the garden, I can answer out of my view of myself rather than from giving her the information she wants. If I have a frustration with myself for not getting more things done, then as she asks the question, I will begin to defend why that particular thing is not done yet. I am defending myself from my own shame, rather than simply trying to give her the information she is simply asking for. It is amazing how answering a different question than the one that was asked can lead to fight.
I think the Gospel gives us the freedom to have self-compassion. It has been interesting as I have practiced self compassion, one of the things I have noticed is that when I cut myself some slack, I can't help but cut others slack too and I end up liking them more, being less irritated by their imperfections.
The second commandment, you shall love your neighbor as you love your self, speaks to this need for loving ourselves. God loving us while we were yet sinners speaks to the same principle. Striving for faith in the gospel, is striving to let Jesus wash our feet, striving to believe we are who God says we are when we believe Him, striving to believe that God likes us and loves us.
So my suggestion is cut yourself some slack. Let God love you, with all your imperfections and notice how your interactions with others begin to change.
Go ahead, give it a try and take the risk!