I don't buy by mail until I check at Yahoo with the query "criticism (company name)" or go to "Dave's Garden the scoop on (company name)".
Beware of something new being advertised like a double flower which had always been single, taller (or shorter) than ever before, or in a different color like a true blue lily.
If you must buy in the big box stores, buy as soon as the plants hit the store. Employees are notorious at ignoring needs of plants.
Don't buy plants or bulbs you can't see. If you have a choice of bulbs in clear plastic or dark green plastic, buy the ones in clear plastic. If the claim is made of 3 bulbs, count them and look for signs of life. Check to see if they are firm or mushy.
Be careful of your zone and don't trust your catalogs. If no gardener in your zone grows a
certain plant, there is a reason. I have tried five times to grow butterfly bush, but it cannot get through the winters. A mere 18 miles away people grow them to 5-6' tall.
3pete

All too often it takes us victims to report the disappointments so others will be alerted as to the true color, height, etc.

I agree with all your points about anything purchased in big box stores. You can add that labels will often give one cultivar name but it's just not true. I bought some purple gladiolus and they're all blooming in pink. Very pretty but not purple. Dahlias have often been wrong.

Of course, labeling has nothing to do with the store who sells a product. This is the responsibility of the vendor who packages it and the grower who grows it. The problem is applicable to all retailers.

True and many vendors will happily promote the latest and greatest without having grown the plant so they truly have no idea of what color it will be. I certainly don't expect vendors to grow every plant they sell.