The reasons behind the General Election result are still wide open, but many people in the Labour Party seem to think it was a victory. This is only true if you think of it as a Dunkirk-like avoidence of what the time the General Election was called looked set to be a complete disaster.
One perfectly plausible way to look at it is as a warning around political hubris. May thought she was guaranteed an enhanced majority. She therefore (a) made the whole election as personalised on herself as possible (b) Stripped the Tory manifesto of key "offers" to vital groups of voters (like the Triple lock for pensioners) so as not to bind her hands in the future (c) Ran a lacklustre campaign that pretty much failed to make a positive case on the assumption that many voters would feel they had nowhere else to go.
The results were not to her liking, and have left people speculating about when she is going to go.
The Labour Party seems to me to be in danger of now throwing away its chances of turning its escape into a victory by:
(a) Assuming it is going to be easy to get the 60 odd seats it needs to win an overall majority, when some of those seats actually have enhanced Tory majorities and are therefore harder to win.
(b) Assuming that a majority can achieved with a "one more heave" approach (in the elegant term of the October 1974 Liberal campaign). I would argue that once the Labour Party is once again seen as a possible "government in waiting" it will be subject to much greater scrutiny over whether it can pay for its promises, what its stance on the European Union is, and whether it can be trusted with the UK's security.
(c) Assuming that it can afford a lapse into internal faction fighting as relieved Corbynistas look to conduct witch hunts against specific MPs who they feel have failed to toe the line, when it is something of a cliche that divided parties put off the electorate. Indeed this is all the more surprising given that many Corbyn supporters have argued that it was the obvious disagreement between the MPs and Jeremy Corbyn that underlay the Labour Party's awful opinion poll ratings up the General Election.