I'm gonna word this all wrong as I'm sleepy but lack of reasonableness or desire to find common ground. There's some sort of distinctively/qualitatively/obviously different behaviour they engage in. And some sort of miscommunication 'common ground' I think people can get to when miscommunications occur, without gunning each other down. Even if someone's a bit weird here and there it's possible/likely that they may be able to explain their miscommunications in a way that makes sense to you roughly.

Maybe they are super passionate about art and they forget to be on time loads when they're painting, but they detriment themselves too - they miss out on their favourite tv show and rush in halfway through - and not just selectively. Then you can go "hey it does appear their mind wanders and they forget all the world around them when they're painting".

I think gaslighters/ing has a very distinctively different property and feel to that. It tends to lack all explanation, and they won't give you one/will blame you for whatever the topic is and in a way that truly goes against the grain of what you feel and consider is normal. Someone may even say they're generous and concerned, yet do absolutely nothing that is normal on that area. They may just make up/use a condition you have, and say they're worried, but if you offered e.g. to go to the doctors they may say something like "it doesn't matter anyway, I know you'll lie to them, that's another characteristic of you" - something you don't recognise and find incredibly personally painful, in just real way - and be the 'sole' arbiter of truth.

When you ask for explanations it could be they say that it's you that's making stuff up, again in a way that goes entirely against the grain of your understanding of the world, and you don't feel this with other people.

And no explanations why often. Just "they hold truth". Things that are self-evidently real are false, things that are true are lies/d about.

And maybe a sort of not physical or even 'loud' power trip, but a controlling mannerism, be it institutional/job power over you, relationship at home, whatever.

As a non-expert guess (please research elsewhere) don't start to 'concede yourself'. I.e. if you find yourself having to make explanations for your behaviour that you find psychologically confusing, upsetting, don't. Just if X happened, it did, and you don't need to find extreme novel behaviours of yourself you've never known and no-one else sees. And don't sacrifice that and try to find explanations in yourself. If it means you can (as with perhaps most people) find a common explanation of miscommunication/error etc. fine. But if not, if you have to, leave. Because that's basically 'the start'. Where you are being pulled in.

Now I don't know the details, but basically if you feel like it's a relationship going 'against the grain' of behaviours and explanations, and especially if these only arise for you ("I am only late when painting for you"), then it's possibly serious.