What I also realized was constantly upgrading from one version to another kept around some legacy files that messed up my OS a bit. A clean install might do the trick for those having issues.
Why is such a solution even acceptable? I had no issues before 10.9.3, but if I have to go through a clean install just to fix the issues, there's no way that Apple is going to keep me as their customer.
And you would rather that your $4000 machine kept crashing rather then spending 30 minutes doing something that could fix it?
I switched from Lenovo (which just worked without any problems) to Mac because I thought it's the same quality (it'll just work) with the bonus of allowing me to develop for iOS.
As it turns out, superficial things like the look and feel is better on the Mac, but it's nowhere near in terms of stability. I used my Lenovo for 3 years in work and at home as my only machine, whereas the Mac is in use for 1 day per week and I've already had more crashes on the Mac than I ever had on my old Lenovo.
I just don't have the time or the interest to babysit my laptop.