Things that are Awkward to do by Yourself

Dining at a restaurant
Going to a movie on a weekend night
Bowling
Going to a concert
Celebrating New Year's Eve
Playing Monopoly
Going to Lamaze class
Going to a school dance
Playing on a seesaw
Going to an amusement park
Going to a buffet
Dancing
Minature golf
Patty cake
Hopscotch
Making out
Football (American)
Going to a party
BBQing
Going to the beach
A picnic
Coloring Easter eggs
An Easter egg hunt
Opening presents
Foosball
Air hockey
A foot race
Skipping
Holding hands
Having a conversation
Riding a tandem bike
Volleyball
Badminton
Going to a water park

Some of these are from here, via.