I’m reading the question as "the message that least makes you want to interact with them" (ie, that makes you not want to talk to them).

For me, it’s between when we’ve never spoken before and they approach me with sexual content, or when they announce that they’re "bored".

For me its..

Hey, like this one time... my mum/aunt/ dad / uncle.... used to .... is this normal ??

I'm open to talk to people who are polite and respectful

If they have the same interest as you. Like what ever that maybe.Nice profile photo

The messages that are just "Hi" or "Hey" from people I have never interacted with before and have zero of their own posts that might give me any indication of their personality.

In the past, responding to these led them to asking some kind of fetish questions like if I wanted to see their wife or something about spanking. And as a result, I'm just not responding to those types of posts anymore.

Sexual or politics.
Sexual requires aa vulnerability I ain't willing to open.
Political people are too sensitive and flip out over nothing. Mostly the anti-woke crowd.

Religion.

Mainly to see if they have anything in common with you

Things about their brothers getting molested.

"can I talk to you?"

Anything tbh unless I've been interacting with the user on SW long-term and they are funny af.

Demands or awkward first lines

"do you want to see pics of my wife"

Anything from the IRS 🤔

When it's obvious they just want to use my message box to wank off.

Weird ass conversations/questions

"Hello Madam, I find your profile..."
Come on dog, you gotta be blind.

Hi