Gym Maths

Didn't get out of work in time to do both gym and watch House - and House won. However, I've been pondering gym maths.

There are 200 lockers in the women's changing rooms. So how come every time I go into the changing rooms after pounding the treadmill is there somebody else using one of the lockers adjacent to mine when there are so many others to choose from?

1 in 199 gives the probability as 0.5% of somebody else choosing any one locker (assuming that it's a random process) - which seems low. However, there are 5 adjacent lockers, bringing this up to 2.5%. Given that there are normally about 10 women in the changing room at any one time, brings the probability of one of 'em using one next to me to 25%. So one in 4 visits, I will have to politely negotiate around another semi clothed person to get to my locker.....

I need to get out more.