I got a couple of my shotgun and rifle bullets up to level 50 in Phantasy Star Universe, if I remember. Your skills and stuff all leveled up as you hit things with them, and it took a lot for them to level. Some weapons, such as the shotgun, weren't so bad because they hit multiple enemies at a time. (The shotgun was also the best weapon type in the game, especially in the hands of a Gunmaster.)
Forces and their derivatives had it the worst, though. Level had more of an effect on their abilities so people did boosting parties where they did nothing but spam them until they eventually leveled them. I had a friend that got all of the buffs and debuffs up to 50. On a Cast Acrotecher.
Ah, good old buff parties. I actually didn't mind those so much. I used to plug in an arcade stick, set the buttons to turbo, and then placed weights on them. Then I'd just chat over keyboard of voice comms as they level, switching out wands/TCSMs as they depleted. It was the levelling of actual attacks that was excruciating... sitting all alone in an instance specifically chosen because each enemy could absorb a gazillion hits before dying.
Speaking of tedious stuff though, it reminds of my first day on it playing the beta. After doing the obligatory running around the Colony for 30 minutes trying to work out how to get into a level, I ended up travelling to Neudaiz and found myself in a party of lvl1's fighting lvl5 enemies. We had one Ranger on the team who was lvl4 with a Sniper Rifle, and was the only person that could actually kill anything (we didn't even know Photon Arts existed, so were extra useless). Unfortunately she hadn't yet learned about Photon Charges, and so would run out of ammo after every batch of enemies... and which point we'd all put our weapons away, sit in a circle and talk about how shit we were until her rifle had finished charging again after a few minutes. We'd then walk to the next batch of enemies and repeat the cycle. Good times.
Also, I have no sympathy for someone creating a Cast Acrotecher, lol.
Collecting all the Riddler trophies in AK. Whyyy did I do that.
Because it ransomed the ending away. Which was utter horseshit. I'm still mad about it all.