First congrats on getting a job at Google. That's one hell of an accomplishment. Tell Matt Cutts I said hi
I agree largely with lubujackson and cupcake_death. It really stems from Google's scrappy startup persona at the beginning and their new corporate goals. Anyone can tell that Google is taking more and more space on the search result pages for themselves using design tricks to add spacing, barely highlight the ads at the top, and even going so far as to build their own vertical search engines in the shopping and travel spaces and then inserting them at the top (to be fair Bing does this to an extent as well) pushing other websites down the page where users barely look.
Google claims these moves are in a users best interest, however, when they came online in 2000 the drumbeat was far different and the best interest was to serve up applicable websites. It seems they are slowly pushing towards a 'google knows best' world where "I'm feeling lucky" is eventually replaced with "this is 100% exactly your answer" and there is little need to go anywhere else.
The pushing of Google+ has not helped their persona any. From seemingly pointless integration with Android and YouTube to forced (and very broken) usage of Google+ Local by small businesses and let's not forget that AuthorRank could EASILY have been a partnership with other social media websites but Google decided to force it on Google+ only and then made it a ranking factor (so use it or lose traffic) which is resulting in some spammy queries as shown here: https://twitter.com/YoungbloodJoe/status/318834815837290497/...
Combine all of that with Google's killing off of beloved products, and making some free products paid only (Google apps) and you get many who are fast to wake up and smell the new order of things like smelling salts shoved under our noses. It should be clear that Google is now a pure wall street business and their core focus is no longer serving up the best search results in the form of webpages, but continuing to find ways to increase revenue from their single largest source of income, Google web search.
For some there is a bit of dissonance. For example, loving Android but getting fed up with how Google might treat a small business through their broken local system, or wanting to see the future of the Google self-driving car, but suddenly being aware of Google's growing governmental ties and seemingly lack of caring about privacy protection for some. In a recent interview with Reuters Vince Cerf, a Google Executive, was quote as saying "Google should not force internet users to use their real names" but then went on to say that Google is not forcing anyone to use a real name to use Google services and that users have a "choice" however, he clarifies that users under oppressive regimes seem to get a pass more than those in say the USA,Canada, or the UK. All of this while Google gets nice and cozy with the USA's "National Strategies for Trusted Identities in Cyberspace" a program that seeks to identify everyone online.
http://uk.news.yahoo.com/google-services-not-require-real-na...
side note: Google is not the only one chasing after a day when Anonymity is dead: http://wrightimc.com/blog/2013/03/04/the-death-of-the-anonym...
Finally there's the matter that Google has been much more of a copycat in recent years than an innovator. Google's business model works like this: If it's really popular and a solid brand name, make a ridiculous offer to acquire the company. If not, build your own free version and use the power of the Google homepage / search results / Android / YouTube to push your new version. If successful in either capacity wait until competitors die off, then add lots of advertising/monetize in other ways. If not wildly successful, kill the product. Groupon is making money? Let's off to buy them, Rejected? ok, we'll start "Google deals". Paypal makes money? Let's do "Google Wallet", etc... In 2010 I met a Googler at an investor meetup at SXSW while pushing an idea for an online video startup. Like all the other attendee's he asked what our concept was. My partner and I discussed that we were being tight-lipped but that we'd like to arrange a meeting later. Gave him our card and our elevator pitch, which was highly watered down. 2 months later, yes 2 months, the very basic part of our concept was debuted at Google I/O as "YouTube Lean Back". Now I'm not accusing Google of any misconduct, but either my idea was hijacked and discussed or I think like a Googler, either way it was still far off from the concept we had that we (thankfully) did not disclose completely. If this has occurred even just a handful of times at large tech conferences it could be a reason for small startups to not want to interact with Googlers a whole lot.
Frankly it shows a lack of imagination and integrity at Mountainview, which if I were a long term investor would scare me.. except for the fact that they have those cool little 'moonshots' that could pay of huge later on.
tl;dr - there are a lot of reasons, but it really comes down to the abrupt way in which Google is changing stance to be a corporation protective of their profits and intruding on the spaces that others want to go into business in (that's likely the best explanation for your startup friends). Here's an audio interview that covers more of this in depth. http://www.capturecommerce.com/blog/organic-seo/is-google-ev...
Google is not "evil" but is a company and is doing what any other company with shareholders and stock would/should do. That doesn't always make it right and there are bound to be unhappy users and missteps along the way.