Spa Day is a treasure trove of long buffs.
The Bath with Soaks will give a +2 buff depending on which soak is used (Citrus: Focused, Lavender or the Milk and Honey: Happy, Muscle Relaxing: Energized, Rose Petals: Flirty on adults and Playful on kids). The buff is 8h normally, 12h if taken while the sim is under the effect of incense (which incense doesn't matter, it doesn't have to match the bath).
The massage table has some long duration buffs also, the longest is, I believe, a day long, and doing it while the sim is under the effect of incense doubles the effectiveness.
The Yoga buffs are +1, 8h normally, with the incense doubling the effectiveness to +2, but if the buff is the result of a Yoga class not only will the effectiveness be doubled as if the sim had incense, the duration will be increased to 12h too.