I've had tinnitus for almost as long as I can remember.
I used to get ear infections when I was a kid and I remember sometimes hearing an intermittent or quiet, steady ringing. I even had a ruptured eardrum (painful!) when I was about 12 or 13. My sister used to affectionately kiss me on my ear and the noise and suction from that was really painful!
Then there was the time my friend and I were playing with fireworks. We were tossing them around until one went under a nearby pickup. Being dumdums, we thought the truck would explode, so we both dove for the cracker just as it went off. I remember a minute or two of panic thinking I'd lost my hearing for good, and then slowly regaining my hearing, thinking it sounded like rain.
Then there was the Lightning Bolt concert I went to without any hearing protection. I think the show was something like four hours long and I couldn't hear my friend shouting directly into my ear. My friend managed to scrounge a pair of earplugs for herself, but couldn't find any for me. She suggested toilet paper. Uh. Okay. That was pretty much laughably inadequate. I could hardly hear for days afterwards.
By far the biggest contributor to my tinnitus, though, was getting on a plane with a bad head cold. Holy hell, that hurt. I really, really thought I was going to go deaf. For weeks after, my ears felt like I was at the bottom of the ocean. Everything sounded muffled, the ringing in my ears was enough to become distracting and worrisome. Compared to this, the firecracker was just dumb kids being dumb. The Lightning Bolt show was a questionable decision, but one I ultimately knew I'd get over. But this was oh f*ck, oh f*ck, oh f*ck! I don't want to be deaf for the rest of my life! Thankfully I'm not deaf, but I do have tinnitus. And I always travel with a packet of pseudoephedrine!