http://wiki.guildwars.com/wiki/Dishonorable
You received the Dishonorable Hex because you were repeatedly reported for leeching or abandoning games. It doesn't happen if you accidentally map to another area once or twice.
If you're not satisfied with the groups you party with, try helping them make builds which work better with yours and are more effective in the area you are challenging.
You can also receive the hex for leaving before the team is transported back to town. If only 1 man is standing, and the situation looks unrecoverable, type /resign and suggest other team members do likewise. Most people will then consent and return to town.
If you're not happy with how this works, then don't abruptly leave games that are in progress without the agreement of everyone else. It gives you a bad reputation, by which people will know you don't play well with others.
If you continue with this type of behaviour throughout your life, you will end up alone and friendless. Best advice, learn to get on well with others, discuss your problems and maybe even grow up a little. I know it's a game, but would people play football with you if you routinely left the pitch before the final whistle?
EDIT: Actually if you resigned from AB or rollerbeetle races twice you will receive it. If you're repeatedly receiving the hex, then you need to have a little patience. And if your team mates are being stubborn in pvp, wait for them to die. The hex is just Anet's way of saying if you join a pvp game, be prepared to play it out to the end. See
http://en.wikipedia.org/wiki/Sportsmanship