From the Aikido of San Diego Membership Handbook, by Dave Goldberg Sensei:
Aikido practice should be a joyful experience, and playful most of the time. If you aren’t having fun, you may be treating yourself too seriously. Don’t be in a hurry to master anything. You have the rest of your life to enjoy your training, benefit by it, discover, and grow.
True for Aikido training, and for everything.