Comment by jampekka

Easier said than done. Saying no is not so easy. There's a bit of a weird dynamic that if you could do something that others need help with, saying no can be considered rude, but saying (even if lying) that you don't know how to do it is generally accepted. Usually a boss (or even a colleague) backing in saying no helps a lot.

Also the helping can cause escalation of "demand". First you help with something quick and easy for you, but soon you find "owning" more and more of the task.

It's not dissimilar from the entitled people in open source project bug trackers.