What's "close attention?"
I've noticed someone sitting next to me who splits 3's and 4's against a 10 upcard who sometimes does better than me . . . but for the twenty minutes he's there, his results are virtually meaningless and reflect nothing more than a lucky streak that won't happen often enough to keep him above water.
I played a few nights ago and could not get paid on any double downs. My 10's and 11's vs. dealer's 5 and 6 upcards went down in flames time after time. It happened so much that even the dealer had to laugh.
Just one of those things. I took my shots and they didn't work out.
I'm now less concerned about outcome and more focused on playing as close to perfect as I can. I'm no pro by any means, but I can go for a good long time without losing a count or missing an index play . . . yet even then then there's no guarantee of success, luck being a factor, I guess.
You had some good sessions and luck was on your side. Take the money and be happy. But understand it wasn't anything more than luck because just paying close attention can't possibly give you any real EV, as far as I know.
And after having spent many a nite pushing out max bets in highly favorable situations only to lose my entire session bankroll in a blink or two of the eye, I can tell you that you have zero long term chance of coming out ahead with no EV on your side of the table.