Forget falling out poor sounding earbuds. It's frustrating. It's not that earbuds can't sound great. It's that if they don't seal, you get poor, weak bass and an awful lack of high-end definition.
And every time I put earbuds into my ears, it takes me like 5 minutes to get them pushed into the sweet spot where I get a good seal for great bass and clear distinct highs. And then as soon as I move, they fall out. I don't know if it's just me, or I have small ears or what, but I'm sure that whoever thought up earbuds sure didn't have me in mind.