You should be careful of hyperbole and using words such as "ALL". I have had a Dell 8400 that has been a gem for over 5 years. That one case proves your premise totally false.
But am I alone? Are there few of us? Well golly gosh gee whiz - NO. Customer satisfaction surveys prove you wrong - as shown in the surverys I linked just a couple of posts above. But since you chose to ignore them, I will repeat the information here for your convenience.
The Mac Magazine reported on a survey of consumer satisfaction, just released several months ago rated Apple number one (big surprise in an Apple rag)and Dell number two, ahead of HP, Gateway, Compaq, and others.
http://www.macworld.com/article/142341/2009/08/acsi.html
PC Mag used to do an annual survey also. The latest I could find was 2007. The results are similar to the above survey. Apple is first, PC Mag includes home-built which ranks second, and Dell is third - ahead of all other manufacturers.
http://www.pcmag.com/article2/0,2817,2182831,00.asp
My last computer I built myself, and expect I will most likely build all my one computers in the future because of the of the advantages of cost, quality parts, upgradibility, and absence of bloatware. But that decision does not change the fact that my Dell served me well for 5 years - and still does as a backup and I am thinking of converting it to a dedicated A/V computer.
Perhaps you should follow the wise words of Mark Twain - "Better to be silent and thought a fool, then to open your mouth and remove all doubt." Your only embarrass yourself with your stupid attack on the credibility of others - which is so obviously bogus that it only destroys your own credility.