The humidity and enclosed space.

In environments where there is a high level of humidity, odor molecules can remain in the air for longer and spread out less. Combine that with the closed space and they linger a lot longer.

Gas expands in heat. You haven’t sniped your noxious blast, you’ve nuked the area. Plus, you have items in the shower that smell nice by design and it presents a much sharper contrast.

https://www.youtube.com/watch?v=B3zqFJDJf2Q

TL;DW:

• Farts can smell worse in the shower due to being in a closed space with nowhere for the gas to go.
• The main reason for intensified fart smell in the shower is increased humidity.
• Higher humidity enhances the sense of smell, allowing detection of lower concentrations of odors.
• Water vapor may help smell molecules interact with nasal receptors.
• Gas particles can bind to water vapor, allowing the air to hold more smell.
• Hot showers create steamy water vapor, which amplifies fart odors.

Why are you in my shower smelling my farts?

you should run for elected office.

One could theorize that the poop particles expelled with the fart are better trapped in the moisture in the air, so as you breathe in the very humid air, and consequently your own poop particles, the sensory elements in your nose and sinus have an easier time detecting them. This is partly owing to how the moisture also makes them more likely to stick to surfaces inside your body as they travel your airways on the journey to your lungs, where your poop particles may end up. Hope this helps.

No filter except your ass cheeks. Usually you'd have at least one layer of cloth between your ass and your nose but not in the shower unless its just been that kind of day

Are you using a fart puller?

Sometimes I enjoy the smell

…..what the fuck?

and at worst it smells "interesting".

I hope you never a fart so gross it makes you disappointed in yourself.

...you can smell your own brand?