It seem that,

In one event where there are two temptations to do evil (A and B),
And if there is more pressure to yield to A,
We become more aware of resisting A,
And less aware of resisting B.

After resisting both, we are happy.

However, from the pressure to focus on A,
We are more likely to identify our happiness,
With resisting A, of which we are more aware,
Than B, of which we were less aware.

Once poorly aware of the connection between happiness with resisting B,
Then in a similar event, the more we try to seek happiness,
By distraction, we are likely to yield to B,
Of which we are less aware.

(Especially if B is a physiological desire.)

It also seems that added unrelated distractions from resisting both A and B,
Could distance ourselves even further from resisting B.

It also seems that yielding to one temptation could lead to a more serious one.