What are common mistakes when making Choux pastry?

Question

Accepted Answer

Adding flour before the water boils — uneven starch gelatinisation. Not cooking the panade (flour-water mixture) long enough — raw starch taste and weak structure. Adding all eggs at once — they won't incorporate. Dough too wet or too dry — it should hold a piped shape. Opening the oven during baking — steam escapes and choux collapses. Not piercing baked choux to release internal steam — they go soggy.