In science, you talk about "quantitative" data and "qualitative" data. Quantitative means something you can put a number to-- how many degrees Fahrenheit, how many grams, how many inches, etc.
Qualitative data is softer-- how something makes you feel.
Usually, how much fun something is falls under the realm of qualitative. You might ask participants to fill out a survey, and rate their experience. It's one way to gather data, but it isn't the best way.
To test out the new Toyota Tacoma, Toyota brought in a neuroscientist, and fitted competitors with an electrodermal-sensing wrist band.