I prefer shopping alone, just because my friends and I have different clothing taste and I just hate to wait. With only the exception of shopping with my bf becuase i like watching what clothes he buys and he likes watching what I pick, and there's no rush in anything.
Dining-wise, I prefer to be with friends, but if I'm at work and in a hurry, i eat alone. It takes at least 3 times longer for me to finish food with friends because I talk too much