I was deeply mired in sin once, but praise God! I have been saved from it.
My sin? Stamp collecting. Harmless? Hardly. A stamp is a token indicating that money has been paid. You can exchange money for stamps; you can exchange stamps for money. Stamps even have monetary values printed on them. They are nothing more than an adhesive form of money. The love of money is the root of all evil, and I loved my stamps. I confess, I still have them - but it's only so I can remind myself of how lost I was in sin.
To my shame, I moved on from this sin to another. For a few months, I flirted with the building of landscapes for model railroad sets. Think of it! The universe that God created wasn't good enough for me - I had to go create my own. I was arguing with God over who was the creator and who was the created; trying to take His role; trying to replace Him with myself!
Sorry to deal with serious matters by satire; it's a habit my whole family is in. My point is simply that, if you use a convoluted enough chain of logic, you can turn Mother Teresa into a monster. Before you go jumping off into "X means Y, and Y could be construed to mean Z, and Z implies W, so it's a sin!" - kindly sit back and think about what God's really about. Read two Gospel chapters and try again in the morning.
We don't need to turn over rocks and dig up holes looking for things to brand "sinful". We all know darn well that we fall short in the simple menu that God puts right before our face. Love the Lord with all your heart and all your soul and all your mind. Love your neighbor as yourself. God's will is not complicated. I suspect that we dive into complicated theology in the hope of distracting ourselves from the more imposing command of love. Loving my neighbor is hard, but denying myself such-and-such is easier. I'll focus on that and feel better.
May God's love and wisdom be with us all.