1. You're really not sure how you feel about it.
If you try it on and don't instantly say to yourself, "Yes. This is totally me. I love this," then don't get it. You probably have enough clothes in your closet that you feel lukewarm about already. Save your money for something that really excites you.
2. It doesn't go with anything you own.
Don't let yourself be hypnotized by a pretty display or a well-styled outfit. There's a reason you don't own anything lime green and ruffly yet.
3. You can't think of at least two ways to wear it.
Two ways to wear it using clothes you already own, that is. The last thing you want is to buy a top believing that it will only look good with a certain kind of bottom that you don't own and end up never finding.
4. It requires special underwear you either don't own or hate wearing.
Are you really going to tape your boobs up just so you can wear some dress? Really? Really!?
5. It's a piece of crap.
You know when something isn't well made: the fabric is flimsy, the seams are uneven, the prints don't line up, etc. If you love something, you can probably find a better-made version that will last a lot longer just by doing a little research online ,and if you don't love it, well, you really shouldn't be buying it anyway.
6. You feel the need to change your body in some way to make it work.
"This will be perfect once I lose a few lbs." STOP STOP STOP. Don't do that to yourself—you're perfect just the way you are!
7. It's uncomfortable.
Very few people have the fashion dedication to wear something they don't like the feel of. Don't waste your time convincing yourself that this time, this piece of clothing, will change all that for you. It won't. Just to be honest with yourself and don't waste your money.
8. You can find it for less online. (If you'd just take three minutes to look!)
If you are at a department store and you see something you love, whip out your smart phone and see if you can find it for less somewhere else. Sites like Polyvore aggregate stock from all over the internet, so you can make sure you are getting the best deal possible. It only takes a couple of minutes and it is so, so worth it.
9. You're only buying it because you have a gift card.
Sell that gift card for cash on Cardpool or a similar site. You won't get the full dollar amount, but it's better than buying something that will take up valuable closet space just because.
10. It doesn't really fit that well.
A good fit is everything. And who really wants to get something tailored?! Struggles.
11. You're buying it for someone else, even though you're the person who is going to have to wear it.
Does your boyfriend/mother/best friend really like how it looks? Then let them wear it.
12. You have something specific in mind and it's not exactly what you wanted, but it's close.
The thing you really want is out there. Don't sell yourself short.
13. You can't imagine yourself wearing it more than once or twice.
Such a waste, whatever the reason. Even if it is on sale.
14. You've been shopping all day and you just don't want to feel unproductive.
You're tired. No one makes good decisions when they're tired. Don't try to force it.
15. You feel like you owe it to the sales person for spending so much time with you.
If you don't find something you like, then you are under no obligation to buy. Ever. As long as you treat the sales person with courtesy and respect, they should really be understanding, and if they're not, then they don't deserve your commission anyway.
16. It's the kind of thing you wish you could wear, but never actually would.
This is not to say that you shouldn't push yourself to venture outside your comfort zone from time to time, but be realistic. If you really feel like a certain piece of clothing is just too cool or body-con for you, then you probably aren't going to wear it. Instead, it'll just sit in your closet.
17. You really can't afford it. Really really.
If you can't afford to go shopping, don't go shopping. Walking into a store full of stuff you know you can't afford and want desperately to buy is just mean to yourself and who wants to do that?