"The absence of alternatives clears the mind marvelously" - Henry KissingerYou just bought a brand new pair of pants and bring them back home. You try it on again and this time notice that the waist is actually a little loose. Your satisfaction drops. You regret not having a better fit; in fact, you've already come to expect it. And you blame yourself for not making a better choice- because (or maybe even though) the options at the store were mind numbingly endless.
Sound familiar? Some particular variant of the story must ring true. That is the Paradox of Choice which has been created by our society, and it is something which has been studied closely by Barry Schwartz (who, with one look, you'll find has risen above this ).
Seriously though, how can we avoid this cycle of negative feeling? Well for one, I would acknowledge what you do have, instead of focusing on what you could. Keep things in perspective; it is one thing to err in a critical way, but chances are we are dealing within the realm of minor inconveniences. Finally, learn from the experience, and move on. There's no sense in getting riled up when what's done is done. Keep your focus on what lies ahead, and feel the weight of choices lift off your mind.