I do theoretical research, I love beautiful proofs. The problem is that beautiful proofs can be wrong. Believing too much in Occam's Razor can trick us into equating the simple with the true. As Richard Feynman said:
If it disagrees with experiment, it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is, it does not make any difference how smart you are, who made the guess, or what his name is—if it disagrees with experiment, it is wrong.
For Feynman's key, we need the right door first. Even “useless” basic research has merits, but we need to beware of inventing problems just to solve them (and publish the results).