I've never actually used a trigger warning, because I feel that the things I write and post don't really require them. I would only use them for things that would bother me enough that would make me want to stop reading, like graphic depictions of rape or suicide. I don't think just mentioning something ("he committed suicide") is worth a trigger warning, but if it goes into details, it might be worth a warning. 

I do use content warnings on dA, but I'm selective about when I use them. 

There two issues I see with trigger warnings are (a) you can't protect everyone and (b) unnecessary warnings.

Everyone is wired differently, and there's no way you could ever know what will set one person off as opposed to another. There are just too many possible triggers to actually label every one and warn people away from whatever the post is. The goes to point b, with people trying to do just that. The example that comes to my mind is someone on tumblr posted a picture of a pomegranate cut in half, with red seeds spilling out, and another tumblrkin (what is the name for tumblr users, anyway?) said that even though it was a fruit, it should still be tagged as gore because it had upset them. Really? -_-

I also feel like people who use unnecessary trigger warnings are using them to feel special, or garner shock and/or views.

I think what I'm trying to say - very inarticulately - is that I think some trigger warnings are okay, but don't be a doofus about using them.