It's fun to watch players in an AD&D game get real full of themselves and think they can do stuff that would really tick off a deity but think that because it isn't the PC's deity or the PC has no claimed deity that it doesn't matter.
Oh ho ho ho my foolish little friend. I have news for you. In my AD&D 1E world, the gods are real and they don't give a rat's rear end if you believe in them or are a follower of theirs or not.
No, remember when your character nearly punched that little fella in the tavern for not getting out of your way fast enough? The deity he follows has a soft spot for that little guy for some reason and you just got on a deity's bad side.
The deities in my world have each others phone numbers, so to speak, in my world. They may not like each other, or care much what each other thinks but if they want to lay a curse on your heinie or just drop you because they can, they will do it and deal with your deity (if you follow one) after the fact.
Heck, you may trigger a war of the gods because of your actions and be totally unaware of it, for now.
Gods are god and they are eternal, and bored. They don't need much of an excuse to meddle in characters lives.
So, you ticked off Thor by accidentally shooting his cleric in a battle (an unfortunate bit of friendly fire there). Your PC didn't even know the cleric was a follower of Thor and by the way, your PC wonders, who the heck is Thor anyway?
Guess what? Thor doesn't care. He's ticked, he's a god and he's got your number.