That's probably an extra reason to vote then Dave - if everyone thinks "I can't make a difference" then nobody does, and you never know whether there might be a bigger turn-out this time round. It seems there are more disaffected people out there who might want their voice heard.
The thing with politics in the UK now is that I can't see any party other than the Conservatives winning a majority again. They've got the votes locked in of one of the largest, most consistent voting blocs (and are now being bolstered by the UKIP vote too, having swung into "UKIP Lite" mode), so essentially it seems that the role of other parties is now just to dilute their power. That's one of the reasons that this whole "Corbyn is unelectable" thing doesn't make sense to me.
It seems that the Tories are still destroying things primarily for their own gain, and that's the thing that needs to be stopped IMO. The shit they've pulled with the NHS is unreal, their bullshit over rail privatisation is ridiculous (so a nationalised railway in the UK can't work but we're happy to sell our railways off to national rail services from other countries who then syphon off the profits while we help fund the investment needed in the infrastructure?), the deals they're striking with China for things like nuclear power are total dick, their austerity measures were proven not to work in other countries that tried them and still don't in ours, their funding c**ts are f**king up schools all around the UK, wage regression, massaging unemployment statistics with the continuation of shit zero hours contracts and unpaid work through DWP schemes, etc... Nothing "positive" they're doing makes a dent in all that shit for me.
Sadly though, I see it being another hefty majority for them so it'll be fun seeing where that leads. It'd be nice if we had any idea, but bearing in mind the specatular U-turns May has made since she took power (e.g. the fact we're having another shitty election in the first place) f**k knows what will actually happen - especially with the way that Cameron and Co. made their pre-election promises before and said "If we don't uphold these then kick us out", but then deleted all record of that from their website... I get that no party fully upholds what they say they'll do, but they've got to be one of the most duplicitous parties out there. Their "We're standing up for workers rights" thing is a case in point - the introduction of a 4-figure sum to hold a tribunal to uphold your rights has meant a massive drop in the amount of people trying to take things to employment tribunals, and I highly doubt that's because companies have suddenly started playing nicely. It's like all the working class voters in America who voted for Trump now finding out that they're about to be f**ked over because he didn't care about them, just about their votes.
EDIT: People saying they're voting Conservative due to how they'll handle the Brexit process seems mental too. Leaders from various countries of the now-EU27 have said that they don't know why May, Johnson and David Davis keep saying things that are patently untrue, and it sounds like they're not particularly hopeful that anything much will be resolved when they do all sit down at the negotiating table. That's not a problem for the EU27, but it very much is for us. Similarly, the idea of this election giving May a mandate to do whatever she wants in the Brexit process and have a stronger bargaining position doesn't really make sense either - just ask Alexis Tspiras, Yanis Varoufakis and Syriza.