I like fruit. I do. If you did a statistical analysis of my eating habits, though, I don't think fruit would show up in the top 10. My wife claims that, like all men, my lack of fruit consumption is because I'm lazy. She argues that I'm just too stuck-on-my-plonk to get up and cut up a cantaloupe or core an apple. I thought for a while that she was right, but as the mandarin oranges re-appeared on pre-Halloween-but-never-to-early-Christmas shelves, I realized that the issue isn't my degree of gumption, its purely a usability problem.
When I open a mandarin orange, as I have done for years, I make an elephant. I do it almost unconciously but I love it, my kids love it and its an easy way to make people smile. In a word, its fun! I eat them because they're fun to eat. For me, that's the best definition of good usability there is: I use it because its fun to use.
Consider for moment one of my other favorite fruits: pineaple. Spikey skin and unruly fronds requiring a knife and cutting board. You seem to cut away more than you leave and then there's all the cleaning. I may be lazy, but that isn't fun.
Compare that to our little mandarin friend. Pick it up, peel it anywhere. Make an elephant. Play with the elephant and your kids (or just remember the playing as you make the elephant). When you're done, it goes in the compost...no other clean up.
Consider this story when designing a product. Sure we all know we need to eat fruit, but when it isn't fun to eat, many of us just find excuses not to. The same will happen with your clients and your product. Make sure you have a product that does what your customer needs, but then make it fun for them to use. The best functionality in the world doesn't help anyone if it doesn't get used.
I like fruit. I do. I just like it to be fun. Now, where did I put that pumpkin ;)