This is easy for me. Exaggeration implied on some of these.
1. SFO - Clean, efficient, nice.
2. DEN - A bit removed from the city and lines can be nuts. UA clubs old. Generally good experience.
3. EWR - It has improved dramatically in the past two years or else it would be closer to LAX on the list. Polaris Lounge is great.
4. IAH - Nothing particularly noteworthy but generally good experience there.
5. LAX - Old, dirty, but the UA Clubs are at least nice.
6. ORD - Jaded from perpetual flight delays. Feels more like purgatory than an airport to me at this point. Love Chicago though.
7. Getting hit by a decrepit Wiki Wiki bus at HNL.
8. IAD - All the charm of a minimum security aviation prison.