For me, the biggest thing that destroyed Tibia was Offline Training, I was a fan of skilling, in fact that was what I mostly did in the early days. I enjoyed it, and not afk training..
In those times, I was a paladin, spears fell to the ground and my cap wasn't high (as that character went to max lvl 35 I believe and my skilling journey began in Rookgard) so, I sat there for hours throwing and picking spears at things, waiting respawn and then again.
I remember I had something like 62 distance in my level 15 paladin, which idk if it was high or not but I was playing with rl friends and they were amazed by my dedication and ofc, the damage output I had with such a low level compared to them (they were mid 20s).
It was something new to me, all the "raising skills" thing and I deeply enjoyed the experience. It meant that the more time and work I gave my training, the more profficient I will be, I was always trying to come up with ways or setups to try and make the training routine dinamic and sort of a responsibility (Yeah, I had a routine back then as weird as it may sound...it was something like, if I hunt for 1 hour, then I should train 3 hours).
It all came down to the fact that in those years I was not having a good childhood, school was a disaster for me in terms of relationships, bullying, etc. So..These groups of rl friends I shared this game with (Friends from my neighbourhood) made me feel special for the feats I did.
The one that they even remember to this day is the day I finally reached lvl 20, in celebration. We went for the lone Dragon beneath Greenshore, I still remember I needed 201 experience to advance..So, equipped with crossbow and bolts and my mighty almost 70 distance, I went on ahead, almost died at the end, but survived with almost black health. Everyone was so excited as I was when the dragon finally died, we went to Frodo's Bar and sat there chatting and talking about how I could now get 10k for free (Desert Quest) and if I wanted to do it now. So off we went. Nevertheless.
"You will never forget your first Dragon." Tibia says nowadays, Idk if that holds up now, but I certainly will never forget my first Dragon, my hands were shaking but my friends were there watching me "ascend" to a new hight in my Tibian journey..
Bottom line: Offline Training is something I despise. It took away all the hard work people did for their loved characters and turned it into an stupid automatic system. Why even have skill levels at that point? It's ridiculous.