There are times when I just feel so rubbish that I feel too sinful to pray. What that probably tells me is that, to my shame and in my pride, there are probably times when I do feel good enough. I need to remember that I'm never good enough, but always welcomed because I'm clothed in Jesus' righteousness. He made the way, so it is always open.
Never feel too bad to pray! Feeling too bad means I need to pray, not feel ashamed to.