What does trashing a thread do?

[intrepidity]

11. Trashing by keyword is actually very useful

There are other reasons for trashing individual threads, and most times I've done it have been for non-obvious reasons--like somehow the wording keeps catching my attention to where it is distracting. In my case, it almost always it is not a negative reflection on the thread itself--so it's good that the thread author doesn't know it.

ETA: I especially do this with sad posts, like those about lost loved ones and pets. I read the thread but then have to hide it because it keeps reminding me.