There are several reasons:
1. The cabinets were not prep cleaned and sanded properly. Sanding and cleaning are an essential part of any refinishing process.
In most cases, you can use a 220 sanding pad to scuff the surface and clean with a 50|50 mix of water and denatured alcohol.
Video Tutorial: How to Prep Existing High Use Finishes for Stain or Paint
2. The surface was contaminated with a dusting spray that contained silicone. Silicone is usually impossible to remove.
You can try scrubbing the surface with a strong detergent such as Spic and Span and warm water combination using a gray Scotchbrite pad. After that clean with denatured alcohol full strength. In most cases, you need to strip and sand, but there is no guarantee of success. Test a small area first.
3. The surface was contaminated with a previous wax finish. Wax is also difficult or impossible to remove. Nothing adheres well to wax, and once you use it the wood grain can become contaminated. The wax can penetrate the wood, making future paint or stain finishes or touch-ups difficult or impossible. Even though there is internet chatter about removing wax with 3rd party products or mineral spirits, the risk of failure in re-coating over a wax finish is very high.
GF does offer a lovely General Finishes Satin Finishing Wax, but we recommend the use of topcoats such as our water-based General Finishes High Performance or General Finishes Flat Out Flat for a reliable sealant. We promote glaze effects and stains as other means for adding depth to refinished furniture.
4. The surface was contaminated with an oil based soap.
5. There was not enough dry time in between coats relative to the temperature and humidity. Ideal Conditions are 70 degrees F and 70% humidity. Refinishing furniture in a space that is below or above the 65-75 degrees F range can lead to problems. The colder your space it is, the longer you have to wait between coats. Cold temperatures slow the dry time and affect how quickly the finish will level, harden and cure.
Our easy rule of thumb is; if it is cold enough to wear a sweater it is too cold to apply a water-based finish.