I feel the same way when I'm not playing with other people. Playing DOA by yourself can be a dull experience unless you're trying to pick up a new character. But I generally feel that way towards most fighting games. The fun is where the people are.
Free Step Dodge
FatalxInnocence
AkaShocka
Because you use Ryu. Ryu is boring.
His Reverence
▲ enter the Ayane club.
ToiletMangoes
Don't give up. Find someone you like, it may be someone who is totally different than Hayabusa in order to keep it fresh. Play with more people. Add me if you want to play sometime.
His Reverence
*COUGH*Ayane*COUGH*
*COUGHHH! HHHHHACK.*
Fuckin' throat.
Ayane.
*COUGHHH! HHHHHACK.*
Fuckin' throat.
Ayane.
Force_of_Nature
Learn to use Akira, Lisa or Ayane. DOA is boring if you only fight the CPU.
His Reverence
Akira definitely preoccupies you for quite a while. Very rewarding character.
ToiletMangoes
I cast a vote for Lisa but I might be a tiny bit biased.
Pictured Mind
Use all characters for a while and learn who you find the ost fun. Or just skip the bullshit and pick a really annoying character like Helena. 
Jaguar360
Leon! ...Or what Pictured Mind said
Pictured Mind
Leon is a boss too if you play him right.
Fiend Busa
Lol ill never pick up anyone except the ninjas <3
I tried Ayane but she to complex
I tried Ayane but she to complex
Pictured Mind
BUT THE NINJAS ARE SO OVERUSED MAN
Jaguar360
Hayate!
Fiend Busa
Ninjas 4 lyfe
Rest of cast are scrubs and not badass
Rest of cast are scrubs and not badass
ToiletMangoes
How is Lisa not badass? She is a scientist who has a night job as a luchadora and does some shady spy work on the side. Again, I might be a little biased.
Force_of_Nature
On top of Akira, Lisa, or Ayane. How can I forget the most in-depth character of all Brad Wong? >.< Brad's the definition of a dedication character. Ayane's only slightly more complex than Hayabusa. Hell, Hayabusa's execution is higher IMO thanks to the Expert Hold Izunas.
Force_of_Nature
Also, in terms of execution. The hardest ninja is actually Kasumi, believe it or not.
ToiletMangoes
Force, you might be right. My friend who plays her says she is really difficult to get high damage combos.
AkaShocka
Brad Wong is the hardest to execute, for the DOA cast anyway. Kasumi is easy to spam with but her high damaging combos are hard to do just like Christie. But as far as any fighting game, Akira is the hardest character ever to execute.