I am in year 11 and i have to do work experience in a few weeks, i'm worried I might work in a crappy place such as a retail store etc, will this affect the rest of my life or is it just a minor experience of a working environment?

Well I did work experience in a school with a class of 5 year olds, put me off children for life! But I think you mean career wise hehe generally work experience is a good insight into how the sort of working environment you are interested in works, and may give you a few good contacts if you work hard! But I dont think it would stand out that much on a CV, most places want 2-3 months previous experience if they want any!