How many cards do you carry? and do they give you the best cash back options? I suggest to carry around 3-5 cards in order to get the most cash back.
Here’s my list of the best Cash Back Credit Cards:

Best cash back cards for groceries/drugstores:

• 5% Cash Back from AmEx Blue Cash(after $6500 in spending)
• 3.75% Cash Back from Chase Freedom Cash

General Cashback Anywhere on Any Purchases:

• 1.25% Chase Freedom Cash Visa Card

Restaurants:

• 5% Citi mtvU **Everyone can get this card
• 3.75% Cash Back from Chase Freedom Cash
• 3% Citi Professional **$100 bonus too for signing up

Top Cash Back Gas Credit Cards:

• 10% Chase BP Visa Rewards Card, then 5% after 2 months **good only at BP gas stations**
• 5% Discover Open Road Card
• 5% AmEx SimplyCash
• 3.75% Chase Freedom Cash Visa Card
• 3% Chase PerfectCard MasterCard, 6% first 3 months

Office Supplies

• 5% American Express SimplyCash Card *5% gas and Telecom too

Hotel

• Starwood Preferred Guest Credit Card from American Express
• Hilton HHonors Platinum 5 points per dollar on eligible purchases
  

Best Cashback Student Cards

• Discover Student Open Road 5% cash back on Gas and auto maintenance
• Citi Student mtvU 5% cash back on Restaurants and more
• Chase Student Flexible Rewards 1% Cash back on Everything