In Denver recently, I noticed a tour bus unloading passengers near the 16th Street Mall and instantly felt sleepy.
When traveling, I might as well have "tourist" inked on my forehead: I brood about which clothes to pack and make unfortunate selections. I pat my body at odd moments to check on secret stores of cash.
My purse bulges with pharmaceuticals, just in case. I worry about the availability of bathrooms and the intricacies of tipping.
But my most irksome sightseeing habit by far - sleeping on tour buses.
The type of bus doesn't matter.
I've napped on sleek buses blasting icy air at my frozen sinuses and deathtraps air-conditioned by broken windows.
Tour guides also are irrelevant.
Neither the dramatic nor the drunken can keep me awake. Fellow travelers make no difference. I take my siesta whether seated by a disgruntled fellow complaining about the frequent sightseeing stops or a cautious couple carrying pepper spray and flares.
Nor do the destinations alter my behavior. I've slumbered through the ruggedness of Alaska and the towers of Manhattan.
I used to search for the cause of my fatigue.
I never found it.
I can be rested, interested, hungry or cold. I can be irritated with the way my traveling companion blinks or uncomfortable because my stylish slacks are too tight. But eventually my head hangs, my body slumps and I slide toward sleep.
I'm not alone.
Occasionally, I've regained consciousness long enough to notice others bobbing, twitching and snoring, as well. Sleeping seems to be as prevalent on tours as Pepto Bismol.
So I've quit trying to maintain consciousness every minute; instead, I strive to make my snoozing socially acceptable - to drowse with dignity by employing self-taught strategies.
I brutalize the well mannered, the unsuspecting, and the slow in order to claim the window seat, where I brace my head between the glass and the seatback. If startled awake, such support lessens the likelihood of whiplash.
I never lean my cheek or forehead against the seatback in front of me because doing so stamps my skin with red sleep lines that don't fade until long after the museum visit is finished, causing school children to think I'm an animated artifact.
When leaning back in my seat, I vary my head position so I won't develop the sure sign of a sleeper: a flat spot on the back of my head with hair fluttering above it like feathers on road kill.
I practice brief, encouraging phrases: "My, that was a bargain," or "I couldn't agree more," until I can repeat them in my sleep if I sense a pause in my seatmate's monologue.
That way my companion won't nudge me for a response and awaken me prematurely, causing peevishness and petty retribution on my part.
I never fall asleep with candy in my mouth because the result is never elegant.
On some trips, though, I don't have the stamina to bulldoze sweet ladies or shoulder aside strong men, and I get stuck in an aisle seat, doomed to throw my head about willy-nilly, dropping my mouth in a dental pose, while performing aisle-blocking, body tilts whenever the bus corners.
I take comfort during these stressful times by remembering that 40 other aisle occupants are doing the same thing.
They don't pay tour guides enough.