All the glitches I've ever used is the Invincible Sailing glitch, the one where you can walk out of the ship, and mostly wall glitches. Those glitches, to me, can't be harmful to other players unless you're using the Assassin Glitch in SvS. To me, glitches can be good and bad at the same time. They can be used as something just to play with, something to amuse, or they can be used to cheat against others and to gain an unfair advantage.
In my opinion, some of the harmless glitches are the:
- Invincible Sailing Glitch
- Flying Through Island Glitch
- Jumping ship (not in SvS)
- KH Glitch
- And all the other 1,439 of them.

On the other hand, the glitches that can cause harm to others are the:
- Flying Assassin Glitch
- Repairing while sailing
- Wall glitches in PvP
- And the infinite ammo and 3x Lightning/Explosives glitch. (I say these 2 because it just gives people an unfair battle advantage in SvS, but it's ok while fighting NPC ships)

Basically, all glitches that people use and take advantage of to lvl faster than normal, or to seem like they're just
awesome in SvS when they're really
not are the glitches that I have always hated and the ones that I want to see fixed ASAP.
I just listed these to give everyone an idea of the glitches I believe are cheats and which ones aren't.