Leave. Seriously. Don't visit if you can help it. There are other, better places to go now. I only visit because I'm semi-involuntarily hooked.

If you instead mean to ask "It's hard for me to imagine anything positive coming out of 4chan. How did you get value out of that site?":

I prefer to remain anonymous and won't describe my hobbies in detail, but among other things I was pointed to new (to me) bands, books and study resources, sometimes quite obscure. The 'what I read, what I expected, what I got' memes persuaded me to read literature that I ignored when it was suggested elsewhere. I learned a lot about computers on /g/, a lot about cars on /o/, etc. Iirc, those communities were developed earlier than their reddit counterparts. There may have been other car forums, but they weren't as funny. Additionally, the site was always hateful, but much less so than it is now.

I suppose also that it helped with my lonliness. For many years I found 4chan, at it's best, to be a much more sincere place than other more moderated communities. Elsewhere, someone might get banned for a clear and honest opinion on my post if it is unkind. On 4chan, someone might insist that I kill myself.

So if I made a post on 4chan and the worst I got was 'you're stupid', or even positivity, I knew it was genuine because that person had the other options available. Elsewhere, I was not so sure.