Are you talking about the gym? I used to prefer the day time because the gym was like a ghost town. No one was there, no waiting for equipment, not enough people around to feel self conscious.... I'd go after 7 or 8 in the morning when most people were off to work. I hated going at night, especially during the prime "buff guy" work out hours, which seemed to be around 7.
I also didn't mind going to the gym really late at night, again, after the place had cleared out.
I find that the morning or evening hours are best for me where motivation is concerned.
I wonder if it just has to do with your natural rhythm. Lots of people find that they get that afternoon slump around 1, 2 or 3 in the afternoon. Then they might catch their second wind in the evening. I wonder if this is what's going on with you. Your energy is low so you don't have that motivation to keep going at 1, but by 6, you're catching that second wind and can go forever. I'm pretty sure this is the way it is with me. I have good energy in the morning, I'm exhausted at around 2-3, and then my energy picks up after around 6. My gym timing was preference, but it was either in the morning or at night.
Now I work out at home, but I still work out better at night or in the morning. If I venture out doors, it's so hot it's either really early in the morning, or at around sunset. If I could find someone to go out with me after dark, I'd go then, when it's cooled off even more!
"Nothing tastes as good as thin feels!"
"Losing weight is hard. Being fat is hard. Pick your hard."
Total Goal Weight:
I weigh myself every day. It keeps me accountable.