I suppose it goes without saying, but time travel is dangerous. When traveling, avoid your future or past self at all costs. You could run yourself over or, as Futurama points out—become your own grandfather.
This little PSA (and t-shirt) is brought to you by Back To The Future Day. The shirt is new in our Nerd Approved Shirt Store and on sale for only $14 for a limited time!
Product Page (