Beyond just the registrar you pick, try not to pick some vanity TLDs. The ubiquitous ones (e.g. .com and .net) are fine. For example .xyz has a bad reputation (due to its initial low price to register, it became used for many spammers) and might be blocked in unexpected places. Others might lure you in with a cheap first year but charge much higher for subsequent years.

In addition to that, ccTLDs (country code) can be a wildcard, especially if you don’t live in the region served by it. Although rare, the country registry can seize your domain. Most commonly though, many, including .us, do not allow you to mask your personal information (WHOIS privacy). I’ve had a .me for a long time and even though they haven’t been much of a problem, they are also raising the price for renewal faster than an equivalent .com, and so I’ve been thinking of letting that domain go.

If you trust your country’s ccTLD registry and they’re reputable, that’s less of an issue, however.