The psychological phenomenon that the more accustomed we become to something — i.e., the more we repeat a behaviour — the more disinclined we become towards it is a curious one.
No doubt it reveals something about what ultimately drives us: the need for change.
Loathe as we are to process the uncertainty any change brings with it, we still crave it, at least periodically.
However, and this is the curious part, what we become accustomed to we also associate with our sense of self. Its potential loss is a feeling closely associated with personal death, psychologically speaking.
How strange that human beings grow stale and irritable over order, consistency and habit, while at the same time they closely associate it with who they are, at bottom.