Modern branch predictors are pretty sophisticated. But, it is also worth keeping in mind that you can do pretty good, for a lot of codes, by predicting simple things like “backwards jumps will probably be followed.” Because a backwards jump is probably a loop, and so jumping backwards is by far the most likely thing to do (because most loops go through more than one iteration).

And a lot of programmers are willing to conspire with the hardware folks, to make sure their heuristics work out. Poor branches, never had any chances.