The loudest concert for me was Cheap Trick in the early 80's while I was in college. I was sitting at the seventh row from stage in a relatively small theater. My ears were ringing for almost a week afterward.
My tinnitus started almost 20 years ago after a company Christmas party. There was a hired band and a dance floor. They were playing so loud that I thought my ears were going to bleed. I got quite depressed for a while after the onset of tinnitus.
And then a few years later, I went to a HiFi store called Harvey Electronics in NYC looking for some new speakers. If you live in NYC area, you've probably heard of them. They're no longer in business. Anyway, the sales person was showing me a pair of Sonus Faber. He put on some Dire Straits and cranked up the amp to an insanely loud level. Stupid me for not reacting to it and just sat there listening. My tinnitus got way worse afterward. Ever since that incident, I always carry earplugs with me, and be very conscious about protecting my hearing.
These days, my tinnitus flares up once in a while, but I've learned to live with it and no longer let it bother me.