"Expectations are just predetermined disappointments"

This was a quote that I heard today from my boss. I thought it was really interesting. I'm still trying to figure out whether or not I agree with it. On one hand, it seems pretty grim and cynical. Is it really true that I can't really expect anything from anyone else? Should I stop setting expectations for myself also? But then I think about what the bible teaches me.

"Therefore I say unto you, What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them." (Mark 11:24 KJV)

What I hear in this passage is that I can go ahead and set my prayers (and expectations) on certain things and they really will come to be.

But then what about all those times that I expect things and they just don't happen. It's easy to say "Oh well, I guess it just wasn't God's will." But that doesn't always seem like a valid answer.

I'll give you an example. I'm expecting a pretty serious healing right now. I felt God move me and I responded (okay, I'll admit, my response time was much slower than it should've been) by donating my glasses to an organization. My action was done out of the faith that if God really was the one who wanted me to step out in my faith, then He would respond according to His word. So I've been walking around now for a few weeks without glasses or contacts and things still look blurry. I have been truly blessed in that I haven't suffered from headaches (in the past, even a few minutes without eyewear meant serious migraines), and my eyesight is definitely better than it was on day one. BUT... I'm still not at 100% capicity and I'm frustrated!

What am I doing wrong?