Probably the most painful thing for software developers is to be restricted in technology choice which they want to use in a development. You pay for a conference ticket, listen about new cool frameworks, development approaches or tools... Then you return to office with huge enthusiasm and desire to try at least something on real project. Unfortunately such initiative very frequently meets resistance from different sides: team members don't want to learn something new, a manager thinks it is risky, a product owner hurries with a next release, etc.