Innocuous reasons for using Tor:
How one woman hid her pregnancy from big data. It's an article about a sociology professor in the states who used her pregnancy as a chance to experiment on the lengths you'd have to go to in order to avoid all those annoying unsolicited e-mails/targeted ads about pregnancy products.
Big data really does get everywhere. It would be interesting to know how many people on this thread realise that in google's terms and conditions for a gmail account you give permission for google to use your e-mails - not just your address books, not just the header information to do traffic analysis (to find out, on behalf of their paying clients, how many of those targeted ads do you as non-paying user, aka "the product" to be farmed for marketing information, actually respond to, for instance), but the actual content of the emails.
The stuff you wrote to Auntie Flo about your piles -gmail can access that message and target you with ads for haemorrhoid cream. The time you were at rock bottom and e-mailed your oldest and bestest friend about feeling suicidal and she spent a whole evening exchanging messages while she talked you down - gmail can access that and target you with ads for prozac (bit pointless in this country with the NHS, far from pointless in the US where patients are encouraged to ask their doctors for specific medicines), that message where you talked to your sister about your DH's erectile dysfunction - gmail can read that and target you with ads for viagra.
I've watched it happen in real time (very innocuous example - I was chatting to a friend over the other side of the Atlantic about our days at work, we are both scientists - suddenly a targetted ad for an incredibly specific piece of experimental kit popped up, which could only have been there on the basis of our conversation).
The threat to privacy comes not just from government, but from big business. And with everything becoming more connected - you need a gmail account to log onto youtube, need a facebook account to verify your identity on some other apps, etc. etc. Now google etc. would argue that you're supposedly "voluntarily" signing your privacy away by not reading the 60 pages of small print terms and conditions before clicking the "I agree" button. But given the ever-increasing interconnectedness of the online world and the things we now need online access for (banking, tax returns, airline bookings), it's not hard to envisage a future where the choice is "sign away your privacy" or "go off grid and live in a cave."