I'm marginally less concerned about what it means *now* than what it means for the future, if I'm honest. The agenda for the next few years is not exactly something that the Tory party has any control over -- small wonder they've trumpeted the "strong and stable" thing over and over, for want of actually saying anything -- but then the same is true of any party that would be stuck with negotiating Brexit. The EU's position isn't going to change because Theresa May has 450 seats rather than 350, and it wouldn't change if by some miracle (or perhaps some freak accident) it was Corbyn who ended up in office.
No, what really worries me is that all the signs are that we are headed for a landslide of huge proportions that would make 1997 seem a modest lead by comparison. Which means that the Tories will be locked into office for at least another three or four election cycles, and can't in practice be held to account for anything they do in that time. It's unhealthy for democracy to have, effectively, a one-party system for so long. But, if indeed Labour gets reduced to fewer than 150 seats, the Lib Dems go nowhere, and the SNP goes slightly backwards, then that's what we'll be left with. "Strong and stable" is not actually a good thing, in and of itself; Kim Jong Un's regime is "Strong and Stable" (for the time being, at least); so was Stalin's Russia, or Mao's China, etc etc...
The Tories don't register on that scale, of course, but the point is still that actually a strong opposition is vitally important. Theresa May, by pretending it's actually an irritant, is playing a very dangerous game that she has a stupidly high chance of "winning", because I fear that a lot of voters will believe her.
I can't say I'd want to see Corbyn in charge either, but coming a reasonably close second isn't "in charge", it's just giving the strong opposition that creates a stable and accountable government. And, at any rate, he's at least leading a party that's measurably different from the Tories at the moment.
I don't see anything other than a Tory landslide; even Tory supporters should be apprehensive about that outcome.
(As an aside, this whole thing is yet another reason why I hate First Past the Post; it's just so unsubtle. I don't want to give my support to Labour exactly; if I vote for them it's out of a desire to see some strength to the opposition parties. But all the ballot box sees is an X next to Labour, which is as good as 100% support, which is exactly not what I'd want to say. Ho hum...)