Not just companies, politics too. For example, many people were swooning over Obama as The One and soon found out that he's in fact a mere mortal with virtues and flaws like the rest of us. Then they turn against him because "he let them down", as if he could've ever lived up to their unreasonable , super-human expectations.
The reality, of course, is that the world is a messy place and we all do some really good things, and some really bad things, and a whole bunch of mediocre things.
Microsoft makes a seamless office suite & email+calendar solution, Apple makes some really good hardware that leverages airtight software integration, and Google makes Web that much more tolerable to use. Thinking that any of them is Perfection Incarnate - or Beelzebub himself, on the other end of the spectrum - is infantile and counterproductive.