most anons start not wanting to use filter: you want to see what's going on, natural.
but sometimes, the shills are just so obvious and annoying that you want a rest from the pelicans (that was a wave of them, similar to AIM now). So you engage filter.
But then you get all these replies to the filtered posts, and it's even more annoying: enter filter ID+.
Now, what I thought for a while was that since ID blocs every post from that anon, the + was doing the same for the repliers, but i tested it out and it just filters the replies, so no fear of missing much anything important there.
Personnally i wish there was a middle option: a turd (third) filter: the posts of that ID still appear, but a third of their original size, maybe a color change too: that way you can still see their bullshit, but it's smaller and visually easier to skip over…