Ever feel 'blah' for no reason...best tips for 'snaping' out of it?

best mood lifter so far : shopping bargain handbag...
i'm in a teriible relationship disaster with my 7 yrs bf... but a few days ago i get hold of a very rare balenciaga from year 2002, and i'm sooo happy.
 
OK, it's a cliche, but it really works:

Do something for somebody else. No matter how bad you feel, for any or no reason, there is always, ALWAYS somebdoy who is worse off than you are, or just somebody that you can do something for.

And if you do, your own blah-ness, sadness, whatever, will magically disappear, or at the very least be dramatically alleviated.