[Clare:] I keep myself busy. Time goes faster that way. (Prologue.2)
Clare comments on her subjective experience of time. When Henry is away, time seems to move more slowly because she's waiting for him. All she can do is just try to distract herself with work.
[Clare to Henry:] "You made it impossible for me to find you in the present; you said it would just happen when it was supposed to happen." (1.1.2)
Despite Henry's advice to wait for time to unite them naturally, Clare kept searching for Henry. She tried hard to cheat time, because she couldn't stand waiting any longer.
[Henry:] It's a very… compatible kiss, a kiss born of long association. (1.1.101)
Although Henry doesn't remember Clare yet, her physical affection and familiarity with him demonstrates that she has known him for a long time already.
[Henry:] Here all of nature was captured, labeled, arranged according to a logic that seemed as timeless as if ordered by God. […] The museum was dark, cold, and old, and this heightened the sense of suspension, of time and death brought to a halt inside its walls. (1.2.7-8)
The way everything is set in its right place and in chronological time in the Field Museum instills Henry with a sense of divine order, with a sense of unchanging, timeless security.
[Clare to Gomez:] "I can reach into [Henry] and touch time… he loves me." (1.8.201)
Clare seems to say that because Henry loves her and is tangible to her, time feels tangible to her, too. It's as though she's living their past and their future with him in the present.
[Clare:] We didn't think the library was funny-looking in its faux Greek splendor, nor did we find the cuisine limited and bland, or the movies at the Michigan Theater relentlessly American and mindless. These were opinions I came to later, […] an expatriate anxious to distance herself from the bumpkin ways of her youth. I am suddenly consumed with nostalgia for the little girl who was me. (1.9.33)
Clare realizes that growing into an adult has caused her to look down on her hometown, mostly due to her own need to prove to the world and to herself that she has chosen a different life.
[Henry:] "Bobby and his girlfriend ought to be listening to The Cure if they want to dress up. But instead they've stumbled into this thing, punk, that they don't know anything about." (1.9.438)
Henry makes an interesting observation here. Why is it that some people grow up with music that was popular way before their time?
[Clare:] "If you could stop, now… if you could not time travel any more, and there would be no consequences, would you?" [Henry:] "If I could stop now and still meet you?" [Clare:] "You've already met me." [Henry:] "Yes. I would stop." (1.9.449-452)
Henry admits to Clare that time travel has no luster, no exciting appeal for him now that he has met her. What's most important to him now is to stay with her in the present.
[Clare to Richard DeTamble:] "But don't you think […] that it's better to be extremely happy for a short while, even if you lose it, than to be just okay for your whole life?" (1.11.107)
Clare believes that the short, fleeting moments of happiness are what life is all about, even if they leave you with sadness when they're gone. She poses an interesting question here. What might be the advantages of never allowing yourself to fully experience moments of happiness in life? The disadvantages?