Force quit mail and itunes more than 80% of the time

For the past 6 months, I have had to force quit iTunes, as well as Mail -

at times the Quit command under File is greyed out.

I quit and nothing happens.

Then I force quit.

Why so often?

What can I do or not do?

Just concerned since this is not great to do all the time.

Thanks in advance for telling me if it's ok

or explaining what can be causing this.