Well I thought this was funny and worth sharing.

Thought I saw a tactical shot, did not calculate it concretely, rushed into it and noticed that I actually blundered.

I was about to hit resign but he beat me to it and resigned first.  

Black(me)'s last move was Qa5 . We both had about 5 minutes left on our clock. My opponent to move ... do you really think he ought to have resigned here? 

lol...that is pretty funny. 

Actually I thought white may be lost but luckily the After Qxa5 the rook is protected.  Otherwise you know, something like Bd6 Kg8 Bf7 Kf7 Qa5 and Re1 might have been mate.

Yep - Bd6+ and Bxf7+ and Qxa5 wins the queen and conveniently covers the back rank mate

Wafflemaster beat me to it

Yup.  Dan Heisman calls these (my blunder) quiescent errors as you are not calculating a forced line tilll quiescence (that's fancy talk for "until the smoke has cleared / no more forcing moves left").

I missed Bd6+ followed by a clearance sacrifice by the other bishop to snag my stupid looking queen.

My opponent missed the same thing.   Instructional for many reasons! :)

lol

Ironically I was just looking at a thread where people were debating whether it is "honorable" to resign.

You're supposed to smile knowingly about it (without feeling the need to give the solution away). 

Fancy talk indeed (and not terribly enlightening either, near as I can tell).

@waffle/jmb : Very astute of both of you for truly calculating it till quiescence. That back-rank idea was the final trick :)

The problem with that though is that such examples only have a point if you actually see the move.  If you don't...you're still likely to have to resign.

@waffle/jmb : Very astute of both of you for truly calculating it till quiescence. That back-rank idea was the final trick :)

I think it just means, don't forget to look at the checks can captures (not just on the board, but also in whatever line you're calculating).

At least that's how I take it.  The "... until position is calm" seems a bit subjective.

All it really seems to me to be doing is restating the obvious--Yogi Berra's "it ain't over till it's over"--by using a thesaurus. 

I think coming up for a term for a common error (however obvious it may be to some) is still a good thing.   Purdy has his "biff' moves ... helps people remember them better. 

Update:

As silly as it sounds, what is "Common sense" is really subjective for chess players.  A strong player with some natural talent for the game doesn't need to be told to do a ton of things a weaker player needs to read up in a book or get coached/mentored on.

But why can't we just say to beginners "don't forget to look both ways before crossing the street" ? (haha)  Because that's not how we play chess is it?

I suspect what all experianced players notice first is:

Undefended pieces at: a5, d5, g5, and e1.  (This is what lead to the fork right).

Quite literally next, I believe we see:  Indirect pressure across the 5th rank (undefended pieces) across the e file (undefended piece).

Then next we notice the backrank pattern (3 pawns in front of king, only 1 rook  on back rank, two enemy rooks on open files).

And now with those tactical cues we look at forcing moves, especially  ones that clear the 5th rank or e file.

Seems obvious right?  But how many of us noticed white was threatening to win a pawn on f6?  How many of us even noticed the knight at all?  I sure didn't  The lack of filtering for important patterns and pieces makes it a terribly difficult game for beginners.

All this to say, I agree with Andy's sentiment that such bits of advice may not be very useful actually.  What we're actually doing is referencing patterns.  And building these patterns is how people get stronger, not because they're so careless as to not look to see if they're dropping pieces (well ok most of the time anyway).

  Black Qa5 is the one move that creates a lost game and the only move that gives white a win.

Also 1.Bd6+ Re7 2.Bxe7+ Ke8 3.Bb4! is needed for the combination to work.

My opponent resigned before I did

Now that is funny!

Good point hicetnunc.