I listen to everything and anything. With me, there is no set genres, just hit shuffle and see what comes up. Pandora, Aimp, Spotify Web, Youtube. My lastfm is riddled with tracks varying betwixt artists and genres. =D
I really like motivation songs going into or preparing for a big 20 min boss battle though. But grinding or chilling, it is anything =D
To get the Spark back ya need to set in-game goals for yourself. That is how I stay motivated to play. I do get bogged down by seeing hackers and lag everywhere but as long as I stay driven to achieving my in-game goals, I am brought back up.
There is a "Goals and Achievement" thread worth looking into on people who have goals to reach in Maple before they call it. It really does help if you are feeling the need for something to look forward to.
Also you can take breaks and find fun outside of Maple Story, when your spirits are up you can go to the website and keep up with the happenings of Maple or decide it isn't quite time yet to return and go about your day.
Make friends outside of Maple and add them to your favorite social media then tell them about the game and party with them to show them the ropes, this would be good for your motivation as well. Helping out your friends.
Try not to let the negative consume you, fight the Black-Mages influence of dread and despair and surround yourself with the Aura of Positivity. (=
Short -term goals:
Get to level 100 on everyone I created on the server I play on. *Only 1 more character to go!*.
Zak Helm on everyone I created on the server I play on (1 more needs one and he is the toughest to get it because he is a perm-beginner).
Get to 250 on everyone I created on the server I play on.
Get guild emblems for my guilds.
Get max legion character slots open.
Horntail Pendant or any Horntail related accessory on everyone I created on the server I play on.
EDITED: Yay narrowing in on my short-term goals. F2