If it’s a sudden thought that just popped into your head or if you just glanced at a girl and noticed she is dressed provocatively it’s not a sin. What makes it a sin is if you entertain the thought or keep looking at the girl in lust. I think the thing I hate the most is women who dress inappropriately for church. Spandex and see through attire is not acceptable in church in my opinion. I remember greeting people as they came into the church and this woman came in with this silky see thru dress and the sun coming in the door right behind her just revealed everything and I quickly looked away thinking why would you wear that anywhere much less to church. Like I don’t want to see that especially when I’m worshipping in the Lord’s house of all places!!