It's actually REALLY FUN TO CHALLENGE YOURSELF!
My greatest moments of growth and personal improvement have been from playing tough opponents or with a partner of lower skill. Every match that I have lost has provided me with information to analyze so that I do better!
I learn from others qualities, play to my opponents weaknesses and I play to my partners strengths. These are key components of my tennis game.
I have played 3.0 people and 5.5 people and everything in between - and the one constant is that every player has a hole in their game. Find the weakness and give that ball to them OVER AND OVER again!
When I am playing people of a lower skill level - I play to their strengths and make the match tougher for myself.
If it's really easy - I play with my left hand!