Undercuts are bad and you should feel bad if you haven't considered how they should work during your mold making process. Poor planning can lead to air bubbles, excess flash, and/or damaged parts.

If you're doing a two-part mold, you will likely be better off if you cast the part separately, rather than trying to mess around with an undercut. Chances are your home setup looks like this:

....and not like this:

It's definitely something you want to think about while sculpting. If you have poorly done undercuts, your final piece will require more work than if you skipped undercuts altogether. Don't be like this guy:

JFC just look at that. Absolutely awful. Disgusting, even.

I like them but I don't have one.

Wet cue ball cut.

Bad

Depends on tire condition of your opponent. If you think you can pull it off with a fresher set and have a pit crew that is somewhat competent it can be really effective at gain position but it's a gamble isnt it

If you don't have an ironic mullet are you even Australian?

It's a scam by Big Barber to make you visit three times as often

They're good if you can use the fresh rubber after your pit stop to overtake the car ahead of you.

They're bad if your opponent does that to you.

Undercuts are good if you're OK with them not being perfect after a couple of days, and if you either have an extremely steady hand at weird angles or a partner with an extremely steady hand as well. I've maintained many a partner's undercut in my day being as queer polyam person and they're a lot of work to maintain but with a steady hand and a decent beard trimmer they're worth it. Also you can practice just maintaining it every day a little bit and you'll get good quick with the trimmer.

Or just spend tons of money to go to the stylist once every couple of weeks and have them maintain it but that's expensive.

I like mine but I also don’t mind touching it up every couple of days so ymmv

I'm pretty gendered about it on an aesthetic level. I maintain my partner's for her and i think it's cute, but i see those old pictures of like skrillex and i think they need a better haircut so for me it's a cut that looks good on the femme side of presentation and less so on the masc side and i can't justify this at all don't make me.

I think they're nice, but yeah, if you're like me and don't like to maintain your hair it's gonna get weird