On the rare occasions that I am impulsive and do not plan carefully, I almost always come to regret it. It might be a financial choice or a purchase, or a combination of these things to try and make myself feel better in the short term, but ends up being at the detriment of long-term happiness.
For travel in particular, I get a lot of enjoyment from the planning phase which makes impulsive flight booking only to end up cancelling (for a fee) the most mindless of all.
Alcoholics addiction is driven in part to having very little to feel happy about, so they try and find it in a bottle. I don't drink but I absolutely see that trait in myself when it comes to food and consumerism. But by planning, I can regain a little control.